000155   Tiwari S N;Dubey K K;Singh J;Shukla S N (Physics and Electronics Dep, Dr. R.M.K. Avadh Univ, Faizabad-224 001, Email: sachida_shukla@yahoo.co.in) : High voltage gain amplifier developed by modifying conventional darlington pair amplifier circuit. Ultra Scient phys Sci 2008, 20(2), 319-24.

Conventional Darlington pair is a popular circuit for amplification of small voltage signals and significantally used in many important applications. First time we have proposed a modification in CC/CE Darlington pair amplifier by replacing one BJT of the pair by FET with inclusion of a biasing resistance RP which produced some unseen results. We observed that the modified amplifier circuit produces high voltage gain with significant bandwidth. This circuit may be very useful for amplification of small signals with high gain in mid frequency bands and beneficial for various analog communication applications.

9 illus, 9 ref

000154   Sunil Kumar;Shailesh Singh;Niraj Singh; Virendra Singh (Physics Dep, T.D.P.G. College, Jaunpur-222 002, Email: n_nirajsingh007@rediffmail.com) : Field distribution in the focal plane of a paraboloidal reflector antenna. Ultra Scient phys Sci 2008, 20(2), 365-72.

The electromagnetic field in the focal plane of a finite axially-symmetrical paraboloidal reflector illuminated by plane wave of arbitary polarisation incident nearly normally at vertex, has been investigated. This paper describe the investigation, explains the method, and summarizes some of its results. The reflector is assumed to be of a focal length which is large compared with the wave length of the incident wave, and the plane of aperture is assumed to be about halfway between the focus and vertex. The purpose is to view of the diffraction pattern in the focal plane by treating the current induced on the concave surface of the reflector, so that the electromagnetic effect due to them on one part on the surface is taken into account at another by means of waves of current and charges on the paraboloid.

1 illus, 10 ref

000153   Srivatsa K M M;Bera M;Basu A;Bhattacharya T K (Electronic Materials Div, National Physical Laboratory, New Delhi-110 012, Email: kmk_srivatsa@mail.nplindia.ernet.in) : Antireflection coatings on plastics deposited by plasma polymerization process. Bull Mater Sci 2008, 31(4), 673-80.

Antireflection coatings (ARCs) are deposited on the surfaces of optical elements like spectacle lenses to increase light transmission and improve their performance. In the ophthalmic industry, plastic lenses are rapidly displacing glass lenses due to several advantageous features. However, the deposition of ARCs on plastic lenses is a challenging task, because the plastic surface needs treatment for adhesion improvement and surface hardening before depositing the ARC. This surface treatment is usually done in a multi-stage process- exposure to energetic radiations, followed by deposition of a carbonyl hard coating by spin or dip coating processes, UV curing, etc. However, this treatment can also be done by plasma processes. Moreover, the plasma polymerization process allows deposition of optical films at room temperature, essential for plastics. The energetic ions in plasma processes provide similar effects as in ion assisted physical deposition processes to produce hard coatings, without requiring sophisticated ion sources. The plasma polymerization process is more economical than ion-assisted physical vapour deposition processes as regards equipment and source materials and is more cost-effective, enabling the surface treatment and deposition of the ARC in the same deposition system in a single run by varying the system parameters at each step. Since published results of the plasma polymerization processes developed abroad are rather sketchy and the techniques are mostly veiled in commercial secrecy, innovative and indigenous plasma-based techniques have been developed in this work for depositing the complete ARCs on plastic substrates.

7 illus, 44 ref

000152   Srivastava S K;Bahadur A;Singh P K (NO, Kamla Nehru Institute of Physical and Social Sciences, Sultanpur, Email: amar.b.007@gmail.com) : Surface plasmon satellites in 2p core-level spectra of heavy transition metal dihalides. Ultra Scient phys Sci 2008, 20(2), 315-18.

X-Ray Satellite spectra arising in 2p core level of heavy transition metal dihalides are calculated using plasmon theory. The energy separation and relative intensity attributes to the surface plasmon excitation and agreed well with the experimental data observed by D.C.Frost and M.Okusawa. The importance of surface plasmon oscillation is verified in satellites of heavy transition metal dihalides by comparison of experimental spectra.

4 tables, 22 ref

000151   Srinivasan R;Ramachandran K (Physics Dep, Thiagarajar College, Madurai-625 009, Email: r_srini2067@yahoo.co.in) : Thermal diffusion in nanostructured porous InP. Bull Mater Sci 2008, 31(6), 863-8.

Nanostructured porous InP samples were prepared by electrochemical anodic dissolution of InP for various current densities and etching periods. The samples were characterized by SEM and photolumines-cence (PL) where a blue shift was observed in PL. Thermal properties studied by photoacoustic (PA) spectro-scopy revealed one order decrease in thermal conductivity of porous InP compared to the bulk. Further it is shown that the thermal conductivity of porous InP decreases with decrease in size of the particles.

5 illus, 3 tables, 22 ref

000150   Singh Y P;Das R;Singh R A (Physics Dep, Govt. Women's Polytechnic College, Sagar-470 001) : Vibrational studies of pharmaceutically imporant carboxylic acid's monomers and dimers in ground electronic states. Proc Natn Acad Sci India-Sect A 2008, 78(Pt 2), 171-8.

Absorption spectra of formic, acetic and bcnzoic acid's monomers and dimers are recorded by FTIR spectrometer. Assuming C_s point symmetry, vibrational assignments for the observed frequencies have been proposed. The spectra exhibit distinct features originating from low frequency vibrational modes caused by intra-molecular motion. Experimental frequencies arc compared with those calculated by GF matrix and AMI methods.

7 illus, 31 tables

000149   Singh S B, [et al.] (High Pressure Physics Div, Bhabha Atomic Research Centre, Mumbai-400 085, Email: dspatil@barc.gov.in) : Optical and mechanical properties of diamond like carbon films deposited by microwave ECR plasma CVD. Bull Mater Sci 2008, 31(5), 813-18.

Diamond like carbon (DLC) films were deposited on Si (111) substrates by microwave electron cyclotron resonance (ECR) plasma chemical vapour deposition (CVD) process using plasma of argon and methane gases. During deposition, a d.c. self-bias was applied to the substrates by application of 13.56 MHz rf power. DLC films deposited at three different bias voltages (-60 V, -100 V and -150 V) were characterized by FTIR, Raman spectroscopy and spectroscopic ellipsometry to study the variation in the bonding and optical properties of the deposited coatings with process parameters. The mechanical properties such as hardness and elastic modulus were measured by load depth sensing indentation technique. The DLC film deposited at -100 V bias exhibit high hardness (~19GPa), high elastic modulus (~160 GPa) and high refractive index (~2.16-2.26) as compared to films deposited at -60 V and -150 V substrate bias. Study clearly shows the significance of substrate bias in controlling the optical and mechanical properties of DLC films.

7 illus, 2 tables, 15 ref

000148   Singh K K;Altaf M;Jaipal Singh;Balraj Kumar; Singh A K;Lalmani;Koul B L (Physics Dep, Banaras Hindu Univ, Varanasi-221 005) : Observations of unique whistler-triggered VLF emissions at low latitude Indian ground station Jammu (India). Ultra Scient phys Sci 2008, 20(2), 387-92.

A detailed analysis of the very low frequency (VLF) wave data obtained during whistler campaigns under All India Coordinated Program of Ionosphere Thermosphere Studies (AICPITS) at the low latitude ground station Jammu (geomagnetic latitude = 22° 26' N, L = 1.17) has yielded two types of unusual and unique whistler-triggered VLF emissions. These include (1) Whistler-triggered hook VLF emissions and (2) Whistler-triggered long enduring discrete chorus VLF emissions during night time. Such types of whistler-triggered VLF emissions have not been reported earlier from the ground observations at low latitudes. In the present study, the observed characteristics of these emissions are described and interpretated, Dispersion analysis of these emissions show that the whistlers have propagated along a path with L-values lying between L = 2.4 and 3.6, suggesting that these whistlers are to be regarded as mid-latitude whistlers. These waves could have propagated along the geomagnetic field lines earlier in aducted mode or in a pro-longitudinal mode. It is speculated that these emissions may have been generated through a process of resonant interaction of the whistler waves with energetic electrons.

2 illus, 10 ref

000147   Sangeeta;Sabharwal S C (Crystal Technology Laboratory, Technical Physics and Prototype Enginee, Bhabha Atomic Research Centre, Trombay, Mumbai-400 085, Email: sangita@barc.gov.in) : Thermoluminescence and nonstoichiometry in optical crystals. Proc Natn Acad Sci India-Sect A 2008, 78(Pt 2), 163-70.

Thermally stimulated luminescence (TSL) from well synthesized crystals W₅ of PbWO₄, CdWO₄, Y₃ Al₅ O₁₂, Bi₄Ge O₁₂ and LiB₃O₅ characterized by XRD and DTA has been studied by TSL is found to be useful in detecting minute nonstoichiometry in these oxide crystals.

10 illus, 25 ref

000146   Rajnikant;Dinesh;Kamni;Sharma B;Lotus S;Gupta K (Condensed Matter Physics Group, Physics Dep, Jammu Univ, Jammi Tawi-180 006, Email: rkantverma@rediffmail.com) : Comparative crystallographic analysis of the X-ray structure of three cholest-based steroidal molecules. Indian J Chem-Sect B 2007, 46(11), 1855-9.

The molecular and crystal structures of (+)-4-cholesten-3-one 1 cholesteryl chloroformate 2 and cholestcryl-caprylatc 3 have been determined by using X-ray crystallographic and computational techniques. All the three compounds crystallize in the monoclinic space group P2₁ with unit cell parameters: a=10.683(5)Angustrum, b=7.861(2), c=14.616(2), (3=105.8(2)° for [1 ]. a=12.294(2)Angustrum, b=9.399(8), c= 12.787(2), β=113.3(1)° for [2] and a = 12.778(9), b = 9.201(4), c = 14.063(6) A, β = 93.85(4)° for [3], The number of molecules per unit cell in case of each structure is 2. The final R-factor for [1] is 0.054, [2] 0.077 and [3] 0.068. Besides some interesting geometrical and structural features, all the three molecules exhibit C-H...O hydrogen bonding. A comparative crystallographic analysis of all the three molecules has been reported.

2 illus, 2 tables, 16 ref

000145   Raj Kumar;Shukla S R (Physics & Electronics Dep, Dr. R.M.L. Avadh Univ, Faizabad, Uttar Pradesh) : Electrical properties of impurity added systems using <n10< tunneling model. Ultra Scient phys Sci 2008, 20(1), 131-4.

Studied the alkali halides doped with polar impurities theoretically with the help of generalized <n10> tunneling model with electric field applied along <100> direction. The expression for polarization and contribution to dielectric constant is obtained. The results are compared with <100> tunneling system.

1 table, 13 ref

000144   Patel R K;Satyendra Singh;Gaur K (Physics Dep, K.N. Govt. P.G. College, Gyanpur, Bhadohi) : Transport properties of mixed solid electrolyte (1-x) Li₃ PO₄ : x Li₃ VO₄. Ultra Scient phys Sci 2008, 20(1), 173-8.

The measurement of electrical conductivity (σ) and Seebeck coefficient (S) of the studied solid of the system (1-x) Li₃PO₄ : x Li₃ VO₄ with x = 0, 0.33, 0.55, 0.67 and 1.0 have been reported from 500 K to melting point of the solid. All the studied solids show superionic phase just below their melting point. In superionic phase a value and activation energy decreases but the temperature span of superionic phase increases for the solids with the increase in x. The phase transition temperature (T_p) from normal to superionic phase decreases with decrease in x. All the solids are mixed conductors with dominant ionic conductivity below transition temperature T_p.

5 illus, 4 tables, 25 ref

000143   Pandit S R;Dwary B D;Yadav S K;Prasad L B (P.G. Dep of Physics, S.K.M. Univ, Dumka) : Compression of BaS under high pressures. Ultra Scient phys Sci 2008, 20(2), 237-42.

Expanding energy as a function of volume in a Taylor series and using different order Pade' approximants, various equations of states have been obtained which have been combined with quasi-harmonic approximation for free energy to study the compression of BaS crystals at high pressures (up to 80 kbar). The results obtained are reasonaly good, lending support to the equations of state and the method used to extend their applicability.

6 tables, 13 ref

000142   Pande S;Pande B;Pandey K (Physics Dep, Kumaun Univ, Nainital) : MHD modes of oscillations in solar coronal arcades. Ultra Scient phys Sci 2008, 20(1), 27-34.

Made an attempt to study magnetohydrodynamic (MHD) disturbances inside the coronal arcades by solving a pair of second-order two dimensional partial differential equations. MHD modes of oscillations of coronal arcades are investigated. It has been shown that the factors responsible for oscillatory modes give rise to the propagation of MHD waves.

3 illus, 20 ref

000141   Padmakshi Singh;Satyendra Singh (Kashi Naresh Govt. Post Graduate College, , Gyanpur, Sant Ravi Das Nagar, Bhadohi-221 304) : Metal complexes of taurine by paper electrophoresis. Ultra Scient phys Sci 2008, 20(2), 243-8.

A recent technique involving the use of paper electrophoresis is described for the study of the equilibria in binary complex systems in solution. The stability constants of ML and ML2 complex species of some ions Cu (II)/ UO₂(II)/ Ni(II)/ Co(II)/ Zn(II)/ Cd (II) with Taurine were determined at an ionic strength of 0.1 perchloric acid and 35°C. The stability constant of the ML and ML2 complexes of metal - Taurine have been found to be (6.75, 5.89), (7.87, 5.10), (5.81,3.69), (4.35,3.58), (4.35,3.30) and (4.31,3.89) for Cu (II), Ni(II), Co(II), Zn(II), Cd (II) complexes respectively.

1 table, 8 ref

000140   Oommen R;Usharani R (Physics Dep, Avinashilingam Univ, Coimbatore-641 043) : Performance analysis of cascade type solar still. Ultra Scient phys Sci 2008, 20(1), 17-26.

Single sloped cascade solar distillation unit with total evaporation area of 0.996 sqm was fabricated and the performance analysis has been carried out during the months of April, May, June and July in the year 2006 at solar energy laboratory of Physics Department, Avinashilingam University, Coimbatore. Temperatures of water, glass cover and step temperature were recorded at regular intervals using thermocouples. Insolation, ambient temperature, and wind velocity were also recorded on sunny as well as cloudy days The daily distillate output varies between 2000-2500ml on sunny days from 9.00AM to 4.00PM., while the solar insolation varies between 700-870 w/m². The daily distillate output varies between 880-1900ml on cloudy days between 9.00AM to 4.00PM., while the solar insolation varies between 330-700 w/m². The nocturnal distillate output varies between 200-500ml. The efficiency of this solar still was found to be in the range of 20-30%.

5 illus, 5 tables, 3 ref

000139   Nagabhushana K R;Lakshminarasappa B N; Revannasiddaiah D;Singh F (Physics Dep, Bangalore Univ, Bangalore-560 056, Email: bnlnarasappa@gmail.com) : Thermally stimulated luminescence studies in combustion synthesized polycrystalline aluminum oxide. Bull Mater Sci 2008, 31(4), 669-72.

Synthesis of materials by combustion technique results in homogeneous and fine crystalline product. Further, the technique became more popular since it not only saved time and energy but also was easy to process. Aluminum oxide phosphor was synthesized by using urea as fuel in combustion reaction. Photolumi-nescence (PL) and thermally stimulated luminescence (TSL) characteristics of γ-irradiated aluminum oxide samples were studied. A broad PL emission with a peak at ~ 465 nm and a pair of strong and sharp emissions with peaks at 679 and 695 nm were observed in γ-rayed samples. The PL intensity was observed to increase with increase in γ-ray dose. Two prominent and well resolved TSL glows with peaks at 210°C and 365°C were observed in all γ-irradiated Al₂O₃ samples. The TSL intensity was also found to increase with increase in γ-ray dose. The TSL glow curves indicated second order kinetics.

3 illus, 1 table, 18 ref

000138   Murali Krishna M V S;Murthy P V K;Vara Prasad C M;Sita Rama Raju A V (NO, Chaitanya Bharathi Institute of Technology, Gandipet, Hyderabad-500 075) : Comparative study of the performance of a low heat rejection engine with two different levels of insulation with pongamia oil based bio diesel. Ultra Scient phys Sci 2008, 20(2), 405-9.

In the context of fast depletion of fossil fuels and increase of pollution levels with conventional fuels, the search for alternate fuels has become pertinent. Alcohols and vegetable oils are probable means to replace diesel fuels as they are renewable in nature. However, use of alcohols in internal combustion engines is limited, as the properties of alcohol fuels are not compatible with diesel fuels. Hence much emphasis is given to the non-edible vegetable oils as alternate fuels in internal combustion engines. However, the drawbacks of low volatility and high viscosity associated with non-edible vegetable oils call for hot combustion chamber, provided by low heat rejection diesel engine. The crude vegetable oils are converted into bio-diesel by the process of esterification. to reduce the molecular weight and viscosity of crude oil. The investigations are carried out on low heat rejection diesel engines which consist of different degree of insulations such as i) air gap insulated piston with superni crown, air gap insulated liner with superni insert and ii) air gap insulated piston with superni crown, air gap insulated liner with superni insert and ceramic coated cylinder head with esterified pongamia oil (bio-diesel) with varied injection pressures. Performance is improved with high degree of insulation with vegetable oil in comparison with conventional engine with pure diesel operation

1 illus, 2 tables, 8 ref

000137   Mohyeddine S;Somashekar R;Revannasiddaiah D (Physics Dep, Mysore Univ, Manasagangotri, Mysore-570 006, Email: smohyeddine@gmail.com) : Distribution function and microscopic order parameter in the case of a nematic compound. Ultra Scient phys Sci 2008, 20(1), 103-6.

X-ray Laue type diffraction patterns were recorded using the image plate system at different temperatures in the nematic phase of 4,4'-Dihexylazoxy-benzene. From the diffused ring, normally observed in the nematic phase and employing three different models the microscopic order parameter has been computed. The order parameter obtained from this technique have been compared with that obtained form optical method. The distribution function estimated at different temperatures in the nematic phase using Deutsch method has also been reported.

4 illus, 10 ref

000136   Maity T K;Sharma S L (Physics & Meteorology Dep, Indian Institute of Technology, Kharagpur-721 302, Email: shivji@phy.iitkgp.ernet.in) : Effect fo gamma radiation on optical and electrical properties of tellurium dioxide thin films. Bull Mater Sci 2008, 31(6), 841-6.

Gamma radiation induced changes in the optical and electrical properties of tellurium dioxide (TeO₂) thin films, prepared by thermal evaporation, have been studied in detail. The optical characterization of the as-deposited thin films and that of the thin films exposed to various levels of gamma radiation dose clearly show that the optical bandgap decreases with increase in the gamma radiation dose up to a certain dose. At gamma radiation doses above this value, however, the optical bandgap has been found to increase. On the other hand, the current vs voltage plots for the as-deposited thin films and those for the thin films exposed to various levels of gamma radiation dose show that the current increases with the gamma radiation dose up to a certain dose and that the value of this particular dose depends upon the thickness of the film. The current has, however, been found to decrease with further increase in gamma radiation dose. The observed changes in both the optical and electrical properties indicate that TeO₂ thin films can be used as the real time gamma radiation dosimeter up to a certain dose, a quantity that depends upon the thickness of the film.

10 illus, 17 ref

000135   Mahendra Singh (Physics Dep, Jagdam College, Chapra) : Electromagnetic radiation from lightening return stroke. Ultra Scient phys Sci 2008, 20(1), 187-92.

Taking the role of interaction of return stroke ion beam forming current How in preionized plasma channel due to stepped leader, a study on the radiated electromagnetic power in the form of ion Whistler Anomalous Doppler Shitted (ADS) mode from lightening return stroke channel is made. As a result of beam particle interaction the return stroke ion beam is retarded by the plasma wave turbulence in the stepped leader. The current thus generated does not vary linearly. Its variation can be approximated to be of the simple harmonic form. In this paper it is estimated that the only one quarter of the total energy of the return stroke is given to electromagnetic waves.

2 illus, 23 ref

000134   Kumar S;Singh S K;Rana M K (Physics Dep, Agra College, Agra-282 002) : Corrections to CCW predictions for the motion of cylindrical hydromagnetic shock waves in a self-gravitating rotating gas. Ultra Scient phys Sci 2008, 20(2), 201-22.

Effects of overtaking disturbances behind the flow in CCW approach have been included to describe the motion of cylindrical hydromagnetic shock wave in a self-gravitating rotating gas. The magnetic filed is assumed to have only constant axial (Hzo = constant) and variable azimuthal (H_θ0 = r^l/2 Hz) components, taking an initial density distribution as ρ₀ = ρ'e^-λr, where ρ' is the density on the axis of symmetry and λ is a non-dimensionalising constant. Cases of reverse trends of variation of flow variables with inclusion of e.o.d have been highlighted.

10 illus, 4 tables, 8 ref

000133   Khan N H;Chowdhury T E;Huq M (Physics Dep, Govt. M.C. College, Sylhet-3100, Bangladesh) : Investigation of electrical and magnetic properties of YBa₂Cu_3+xO_{7+δ superconductor.} Ultra Scient phys Sci 2008, 20(2), 325-30.

Electrical & magnetic properties of YBa₂Cu₃+xO_7+δ (x=0,0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 1) superconducting materials, prepared by standard solid state reaction technique, is reported. X-iay diffraction pattern of the samples show that the structure of the samples were orthorhombic and single phase. The superconducting transition temperature T_c was determined from DC resistance and AC susceptibility measurement. DC resistance measurement for YBa2Cu3+x07+6 sample with x=0 showed a sharp superconducting transition having an onset temperature of about 91K. The AC resistance measurement also showed that the transition temperature T_c decreases as the copper concentration in the sample increases. The oxidation states of the samples increase with increasing copper content. It was observed that T_c decreases as copper content increases in the samples. The YBa₂Cu₄O_7+δ sample is a suppression of 2nd order phase transition (orthorhombic to tetragonal), which is a well known characteristic feature of YBa₂Cu₃O_7+δ superconductor. The stable oxygen content in YBa₂Cu₄O_7+δ makes the structure thermodynamically stable than the YBa₂Cu₄O_7+δ and as a result, no oxygen vacancies or twin structures are present in the YBa₂Cu₄O_7+δ sample.

2 illus, 1 table, 16 ref

000132   Kailash Kumar;Singh D V (Physics Dep, Agra College, Agra-282 002) : Ionicity and microhardness of binary tetrahedral semiconductors. Ultra Scient phys Sci 2008, 20(2), 249-52.

A sample relation is used to calculate the ionicity (fi) and microhardness of binary tetrahedral semiconductors. An investigation into various crystal parameters and their correlation have been done. Lavin's modification of Phillip and Van Vechten (PVV) theory are discussed and hence ionic gap (E_c), homopolar gap (Eh) average gap (E_p) and ionicity (f_i) are investigated for binary tetrahedral semiconductors. The estimated value of ionicity is then used to evaluate the values of microhardness. The results have been compared with corresponding values reported in literature. A fairly good agreement has been obtained between the results and values reported by other workers.

2 tables, 17 ref

000131   Hargyan Singh;Pawan Kumar;Swarup R (Physics Dep, D.S. College, Aligarh-202 001, Email: rsdsc_alg@yahoo.com) : Hall effect in HTS Y₁₂₃ above T_C under MRF-perturbations. Proc Natn Acad Sci India-Sect A 2008, 78(Pt 3), 245-7.

The Hall effect in high temperature superconductors (HTS) belonging to Y₁₂₃ under magneto-radio-frequency perturbations had been studied at room temperature. The pure as well as praseodymium (Pr) doped yttrium based UTS were synthesized using solid state reaction method. The magneto-potential records with changing magnetic fields and frequencies had been employed to compute the Hall coefficient R_H plasma frequency ω_p, free space wavelength λ_p, relaxation time τ and ac conductivity σ. The doping process seems to reduce the Hall potentials in these HTS samples.

4 illus, 1 table, 9 ref

000130   Gedam R K;Kulkarni D K (Physics Dep, Institute of Science, Nagpur-440 001, Email: rajugedam40@yahoo.co.in) : Structural, electrical and magnetic studies of pyrite and related mineral. Ultra Scient phys Sci 2008, 20(1), 67-74.

The sample of the pyrite and aresenopyrite mineral were collected from Malanjkhand open pit mines of Balaghat district of Madhya Pradesh and Bhimsen Kila Pahar block of Bhandara district Maharashtra State to study the structural and physical studies of the samples in Laboratory. The samples has been characterized by X-ray diffraction technique and revealed that the first sample was possesses cubic crystal structure with pyrite structure and preferred orientation along (311) plane with the space group Pa3 and point group 2/m3. The value of lattice parameter a for the pyrite sample is found to be 5.417 °A and the second sample was possesses monocline structure with arsenopyrite along (210) plane with space group P2₁/c and point group 2/m. The value of lattice parameter a, b and c are found to be 5.741 °A, 5.668 °A and 5.770 °A respectively. The d.c. electrical resistivity measurement have been carried out over temperature range of 300° to 800°K. The temperature dependence of electrical resistivity exhibited activation energies. The magnetic susceptibility value are found to be 96.91 x10^-8m³kg^-1 and 11.09x 10^-8m^{3kg-1 (S.I. unit). These values were compared with the standard data and showed that the samples are having cubic and monoclinic structure, semiconductor behavior and paramagnetic which become ferromagnetic after applied external field.}

4 illus, 21 ref

000129   Dewan N;Haridas D;Shandilya S;Sreenivas K; Gupta V (Physics and Astrophysics Dep, Delhi Univ, Delhi-110 007, Email: drvin_gupta@rediffmail.com) : Influence of temerature stability on sensing properties of SAW NO_x sensor. Indian J Engng Mater Sci 2008, 15(4), 352-4.

Presents the study on the influence of temperature stability of SAW sensor on the sensing properties for NO_x gas. Temperature stable SAW sensor based on 128° YX LiNbO₃ single crystal was developed after integrating with rf sputtered amorphous TeO₂ thin film that act as a temperature compensation over-layer. TeO₂ thin films possessing negative temperature coefficient of delay (TCD) also served as a sensing layer for the detection of NO_x gas. Temperature stable SAW devices are essentially desired to avoid the problem of false alarm, besides the enhancement in the sensitivity and reliability.

4 illus, 4 ref

000128   Das S S;Parija S;Sahoo S K;Mishra S;Dash M R (Physics Dep, KBDAV College, Nirakarpur, Khurda-752 019) : Magnetohydrodynamic mixed convective three dimensional flow and heat transfer through a porous medium bounded by an infinite vertical porous flat plate with periodic permeability. Ultra Scient phys Sci 2008, 20(2), 347-56.

Considers the three dimensional mixed convective MHD flow and heat transfer of a viscous incompressible electrically conducting fluid through a highly porous medium bounded by an infinite vertical porous plate with periodic permeability. The main objective of this study is to analyze the effect of periodic permeability and applied magnetic field on the flow field through a highly porous medium bounded by an infinite vertical porous plate. Assuming the free stream velocity to be uniform, the governing equations are solved and approximate solutions are obtained for the velocity field, the temperature field, the skin friction and the heat flux in terms of Nusselt number (Nu). The effects of the flow parameters characterizing the flow field are studied and discussed with the help of figures and tables.

4 illus, 2 tables, 14 ref

000127   Damle R;Kulkarni P N;Bhat S V (Physics Dep, Bangalore Univ, Bangalore-560 056, Email: ramkrishnadamle@bub.ernet.in) : Study of effect of composition, irradiation and quenching on ionic conductivity in (PEG)_x : NH₄NO₃ solid polymer electrolyte. Bull Mater Sci 2008, 31(6), 869-76.

Prepares, characterizes and investigates a new PEG-2000 based solid polymer electrolyte (PEG)_x: NH₄NO₃. Ionic conductivity measurements have been made as a function of salt concentration as well as temperature in the range 265-330 K. Selected compositions of the electrolyte are exposed to a beam of 8 MeV electrons and ⁶⁰Co γ-rays to an accumulated dose of 10 kGy to study the effect on ionic conductivity. The electrolyte samples are also quenched at liquid nitrogen temperature and conductivity measurements are carried out. The ionic conductivity at room temperature exhibits a characteristic peak for the composition, x = 46. Electron beam irradiation results in an increase in conductivity for all compositions by a factor of 2-3. Exposure to γ-rays enhances the conductivity by one order of magnitude. Quenching at low temperature has resulted in an increase in conductivity by 1-2 orders of magnitude. The enhancement of conductivity upon irradiation and quenching is interpreted as due to an increase in amorphous region and decrease in crystallinity of the electrolyte. DSC and NMR measurements also support this conclusion.

11 illus, 4 tables, 23 ref

000126   Bajpai P K;Shah D;Ravi Kumar (Pure & Applied Physics Dep, Guru Ghasidas Univ, Bilaspur-495 009, Email: bajpai_pk@yahoo.com) : SHI irradiation induced nano scale surface micro-relief's in the polar (010) cleavage of pure and doped TGS crystals. Indian J Engng Mater Sci 2008, 15(4), 334-42.

The resulting image topology change as a function of irradiation is analyzed. The smooth surface of pure TGS shows pits and protrusions when irradiated with SHI beam. The height and dimensions of these micro-reliefs vary with ion beam fluence as well as with doping. The height of the pits changes from 20 nm to roughly 70 nm from pure TGS to 15% alam'ne doped TGS. Observed micro-relief is analyzed considering the lamellar domain structure of TGS. The domain movement induced by the internal bias field created due to irradiation results into piezoelectric compression and stretching forming these features on the surface. The results are used to calculate the internal field developed due to irradiation using the d₃₃ and height of pits formed as reported earlier. The calculated values of internal fields are of the same order as that obtained from hysteresis measurements. This demonstrates that swift heavy ion beam irradiation could be used as a tool to modify the surface nano structures.

6 illus, 1 table, 34 ref

000125   Aruna Singh;Gaur K;Satyendra Singh (Chemistry Dep, K.N. Government P.G. College, Gyanpur, Bhadohi) : Pressure dependent studies of thermodynamic properties of liquids. Ultra Scient phys Sci 2008, 20(1), 165-72.

Ultrasonic velocity and density data are utilized to estimate a number of important and useful thermodynamic properties of nine liquids (water, methyl alcohol, ethyl alcohol, n-propyl alconol, n-butyl alcohol, eugenol, carbon tetrachloride, n-hexane & toluene) as a function of pressure at different temperatures. The calculated properties include adiabatic compressibiliy (β_s), isothermal compressibility (β<84>), thermal expansivity (α), heat capacity at constant pressure (C_p) and at constant volume (C_v) pseudo Gruneisen parameter (Γ), heat capacities ratio (γ), energy of vaporization (ΔE_vap), heat of vaporization (ΔH_vap) and molecular radii (r) satisfactory agreement for all the properties has been found.

1 table, 14 ref

023521   Shashikumar T S;Ragini N;Chandrashekara M S; Paramesh L (Studies in Physics Dep, Mysore Univ, Manasagangotri, Mysore-570 006, Email: lp@physics.uni-mysore.ac.in) : Studies on radon in soil, its concentration in the atmosphere and gamma exposure rate around Mysore city, India. Curr Sci 2008, 94(9), 1180-5.

Concentrations of radon in soil, rate of its exhalation from the ground surface and its concentration in the atmospheric air have been studied in and around Mysore city (12°N and 76°E). Variation of radon concentration in the soil-gas under dry and wet conditions at different depths was also studied. Radon in soil-gas was found to increase with depth and decrease with increase in moisture content of the soil. Radon in soil varies from 0.11 to 11.85 kBq m^-3 with a median of 1.92 kBq m^-3. The annual average values of radon and its progeny concentrations in the atmosphere vary from 15.33 to 47.81 Bq m^-3 with a median value of 24.36 Bq m^-3 and 0.08 to 3.54 mWL with a median value of 0.33 mWL respectively. Good correlations were observed between radon in soil, radon exhalation rate from the ground surface and radon concentration in the atmosphere in these locations. ²²⁶Ra in soil at these locations was also estimated using the HPGe detector. The activity of ²²⁶Ra varies from 11.3 to 74.2 Bq kg^-1. Radon concentration in soil-gas shows good correlation with the activity of ²²⁶Ra in soil. The correlation coefficient was 0.76.

3 illus, 3 tables, 25 ref

023520   Sharma R;Malik R;Lamba S;Annapoorni S (hysics and Astrophysics Dep, Delhi Univ, Delhi-110 007, Email: aalqudami@physics.du.ac.in) : Metal oxide/polyaniline nanocomposites: cluster size and composition dependent structural and magnetic properties. Bull Mater Sci 2008, 31(3), 409-13.

Nanocomposites of iron oxide with conducting polymer in the form of powders of varying compositions have been studied to understand the effects of particle size, cluster size and magnetic inter-particle interactions. The sizes of the nanoparticles were estimated to be ~ 10-20 nm from the X-ray diffraction (XRD) and the transmission electron micrographs (TEM). XRD shows a single crystalline phase for the γ-Fe₂O₃. The presence of conducting polymer was confirmed through Fourier transform infrared (FTIR) spectroscopy. The amount of polymer present in the composite, the transition temperature of iron oxide and the thermal stability of polymer was determined through thermogravimetric and differential thermal analysis (TGA-DTA). The room temperature magnetic hysteresis measurements show reduction in saturation magnetization with increasing polymer concentrations. A low value of coercivity was observed for low polymer composites. On increasing the polymer concentration, the coercivity and remanence become negligible indicating a super-paramagnetic phase at room temperature. Beyond a certain composition, the system shows paramagnetic behaviour which is also confirmed through zero field cooled-field cooled (ZFC-FC) measurements. We also report preliminary results on the magnetic properties of self standing sheets prepared using γ-Fe₂O₃ and NiFe₂O₄ nanoparticles and conducting polymers.

8 illus, 8 ref

023519   Ravichandran K;Muruganantham G;Devakumari G; Avaniraja N;Sakthivel B;Philominathan P (P.G. and Research Dep of Physics, AVVM Sri Pushpam College (Autonomous), Poondi, Thanjavur-613 503, Email: kkr1365@yahoo.com) : Low-cost and simplified fabrication technology to deposit transparent conducting tin oxide films for solar cell applications. Scient Trans Envir Technovation 2009, 3(1), 1-7.

An inexpensive and simplified fabrication technology using perfume atomizer is employed to deposit transparent conducting thin films of SnO₂: Sb (antimony doped tin oxide) onto glass substrates, by varying the antimony doping concentration. The structural studies reveal that the films are polycrystalline in nature with tetragonal crystal structure. The preferred orientation is along the (110) plane for all the doping levels and the degree of preferred orientation increases with the increase in doping concentration in the starting solution. The fine quality SEM and AFM images of the antimony doped tin oxide (ATO) films obtained in this work show that the films are homogeneous and uniform. The sheet resistance is found to decrease with the increase in antimony doping level, attains a minimum value (6.34 Ω/Δ) when the doping concentration is 1.5 at. % and then increases for further doping. Good visible transmittance (>80 %), wide optical band gap (3.52 eV) and the desirable figure of merit (4.39 O^-1) observed in this investigation make these films suitable for low-cost solar cell window layers and other opto-electronic applications.

5 illus, 3 tables, 22 ref

023518   Kshirsagar A;Kumbhojkar N (Physics Dep, Pune Univ, Pune-411 007, Email: anjali@physics.unipune.ernet.in) : Empirical pseudo-potential studies on electronic structure of semiconducting quantum dots. Bull Mater Sci 2008, 31(3), 297-307.

Theoretical investigations of electronic structure of quantum dots is of current interest in nano-phase materials. Empirical theories such as effective mass approximation, tight binding methods and empirical pseudo-potential method are capable of explaining the experimentally observed optical properties. We employ the empirical pseudo-potential to calculate the gap between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) as a function of shape and size of the quantum dots. Our studies explain the building up of the bulk band structure when the size of the dot is much larger than the bulk Bohr exciton radius. We present our investigations of HOMO-LLJMO gap variation with size, for CdSe, ZnSe and GaAs quantum dots. The calculated excitonic energies are sensitive to the shape and size of quantum dots and are in good agreement with experimental HOMO-LUMO gaps for CdSe quantum dots. The agreement improves as experimentally observed lattice contraction is incorporated in pseudo-potential calculations for ZnSe quantum dots. Electronic structure evolution, as the size of quantum dot increases, is presented for CdSe, ZnSe and GaAs quantum dots.

6 illus, 4 tables, 60 ref

023517   Harish Chander;Chawla S (Electronic Materials Div, National Physical Laboratory, Dr K S Krishnan Road, New Delhi-110 012, Email: santa@mail.nplindia.ernet.in) : Time resolved spectroscopic studies on some nanophosphors. Bull Mater Sci 2008, 31(3), 401-7.

Time resolved spectroscopy is an important tool for studying photophysical processes in phosphors. Work investigates the steady state and time resolved photoluminescence (PL) spectroscopic characteristics of ZnS, ZnO and (Zn, Mg)O nanophosphors both in powder as well as thin film form. Photoluminescence (PL) of ZnS nanophosphors typically exhibit a purple/blue emission peak termed as self activated (SA) luminescence and emission at different wavelengths arising due to dopant impurities e.g. green emission for ZnS: Cu, orange emission for ZnS : Mn and red emission for ZnS : Eu. The lifetimes obtained from decay curves range from ns to ms level and suggest the radiative recombination path involving donor-acceptor pair recombination or internal electronic transitions of the impurity atom. A series of ZnMgO nanophosphor thin films with varied Zn: Mg ratios were prepared by chemical bath deposition. Photoluminescence (PL) excitation and emission spectra exhibit variations with changing Mg ratio. Luminescence lifetime as short as 10^-10 s was observed for ZnO and ZnMgO (100:10) nanophosphors. With increasing Mg ratio, PL decay shifts into microsecond range. ZnO and ZnMgO alloys up to 50% Mg were prepared as powder by solid state mixing and sintering at high temperature in reducing atmosphere. Time resolved decay of PL indicated lifetime in the microsecond time scale. The novelty of the work lies in clear experimental evidence of dopants (Cu, Mn, Eu and Mg) in the decay process and luminescence life times in II-VI semiconductor nanocrystals of ZnS and ZnO. For ZnS, blue self activated luminescence decays faster than Cu and Mn related emission. For undoped ZnO nanocrystals, PL decay is in the nanosecond range whereas with Mg doping the decay becomes much slower in the microsecond range.

6 illus, 5 tables, 14 ref

023516   Dey S;Pethkar S;Adyanthaya G D;Sastry M; Dharmadhikari C V (Physics Dep, Pune Univ, Pune-411 007, Email: cvd@physics.unipune.erner.in) : New approach towards imaging λ-DNA using scanning tunneling microscopy/spectroscopy (STM/STS). Bull Mater Sci 2008, 31(3), 309-12.

A new methodology to anchor λ-DNA to silanized n-Si(111) surface using Langmuir Blodget trough was developed. The n-Si (111) was silanized by treating it with low molecular weight octyltrichlorosi-lane in toluene. Scanning tunneling microscopy (STM) image of, 1-DNA on octyltrichlorosilane deposited Si substrate shows areas exhibiting arrayed structures of 700 nm length and 40 nm spacing. Scanning tunneling spectroscopy (STS) at different stages depict a broad distribution of defect states in the bandgap region of n-Si(111) which presumably facilitates tunneling through otherwise insulating DNA layer.

4 illus, 18 ref

022375   Uvarani R;Sivapragasam J (Physics Dep, K.S.R. College of Engineering, Tiruchengode, Namakkal, Tamilnadu, Email: anbuuva@yahoo.co.in) : Acoustical studies on molecular interactions in binary liquid mixtures at 303 K. E J Chem 2009, 6(4), 1150-2.

Molecular interaction studies using ultrasonic technique in the binary liquid mixtures of cyclohexanone with o-cresol and p-cresol have been carried out at 303 K. Using the measured values of ultrasonic velocity, density and viscosity, acoustical parameters and their excess values are evaluated. From the properties of these excess parameters the nature and strength of the interactions in these binary systems are discussed.

1 table, 15 ref

022374   Thirumaran S;Jayalakshmi K;Job Sabu K (Physics Dep, Annamalai Univ, Annamalainagar-608 002, Email: thirumaran64@gmail.com) : Acoustic studies in ternary liquid systems of substituted benzenes with 1-chlorobutane at different temperatures. Rasayan J Chem 2009, 2(2), 424-35.

The ultrasonic velocity, density and viscosity have been measured for the ternary mixtures of substituted benzenes such as chlorobenzene, bromobenzene and nitrobenzene with 1-chlorobutane In cyclohexane at 303, 308 and 313K. The experimental data have been used to calculate the acoustical parameters namely adiabatic compressibility (β), free length (L_f), free volume (V_f) Internal pressure (π_i), relaxation time (τ), Gibb's free energy (ΔG*), acoustic impedance (Z) and molar volume (V_m). Some of the above excess parameters have also been evaluated and fitted to Redlich-Kister polynomials. Weak dipole-dipole interaction is observed in the present systems of liquid mixtures. It is also interesting to note that chlorobenzene is acting as an effective diluent in the mixtures comparing other two substituted benzenes.

6 tables, 23 ref

022373   Suresh S;Vasanthakumari R (Physics Dep, Loyola College, Chennai-600 034, Email: kumarirv@yahoo.co.in) : Growth and characterization of solution-grown tris-glycine zinc chloride (TGZC) single crystals. Rasayan J Chem 2009, 2(2), 441-6.

Good optical quality single crystals (size 30.05 x 18.66 x 7.41 mm³) of Tris-giycine Zinc Chloride (TGZC) were grown by slow evaporation technique from its aqueous solution at room temperature. Single crystal X-ray diffraction (XRD) studies revealed the presence of orthorhombic structure with space group Pbn2₁ and Fourier transform infrared transmission (FTIR) have confirmed the presence of the functional groups present in the single crystal system. UV spectrum showed no significant absorption in the region 200-800 nm suggesting the optical transparency of the grown crystals. The refractive index was measured by the Brewster's angle method. The density measurements were carried out by both theoretical and experimental methods. The Non Linear Optical (NLO) behaviour of TGZC crystals was tested by Kurtz- Perry technique. The dielectric studied was carried out by room temperature.

5 illus, 22 ref

022372   Palaniswamy S;Mayilvanan M;Dharamani A S (Physics Dep, PSG College of Arts and Science, Coimbatore-641 014, Email: palazhamni_5003@yahoo.com) : Classification of functional groups of a phytochemical: gymnemic acid using fuzzy logic. Rasayan J Chem 2009, 2(2), 475-87.

This paper deals with simplest method to identify the active functional groups in phytochemicals. A photochemical is a natural bioactive compound found in plant foods that work with nutrient the dietary fiber to protect against disease. In organic chemistry, functional groups specific groups of atoms within molecules that are responsible for the characteristic chemical reactions of those molecules. The same functional groups will undergo the same or similar chemical reactions. A chemical database is one of the database that exclusively designed to store phytochemical information such as molecular surface properties number atom, position of the atom and bond relation between atom are derived from histogram. Developed a method to find the functional group of clustered phytochemicals which will lead to new millstone in drug discovery.

2 illus, 17 ref

022371   Palaniswamy S;Balasundaram O N (Physics Dep, P.S.G. College of Arts and Science, Coimbatore-641 014, Email: palazhamni_5003@yahoo.com) : Effect of pH on the growth and characterization of glycine sodium nitrate (GSN) single crystal. Rasayan J Chem 2009, 2(2), 386-92.

Single crystals of semi-organic non-linear optical Glycine Sodium Nitrate (GSN) have been successfully grown from three different pH (1.1, 6,0, and 10.8) solutions by evaporation solution growth. In this report we bring out the influence of pH on the optical, structural and NLO properties of the grown crystals. The grown crystals have been subjected to powder X-ray diffraction studies to identify the crystalline nature. Single crystal X-ray diffractometer was utilized to measure the cell parameters and morphology of the grown crystals. The FTIR spectra for the crystals grown at different pH values show variations in the peak intensity. The NLO property is found to be varying with the change in the pH values.

3 illus, 4 tables, 10 ref

022370   Padmanabhan T (IUCCA, Post Bag 4, Pune Univ, Campus, Ganeshkhind, Pune-411 007, Email: paddy@iucaa.ernet.in) : Why does an accelerated charge radiate?. Resonance 2009, 14(5), 499-507.

The fact that an accelerated charge radiates energy is considered an elementary textbook result in electromagnetism. Nevertheless, this process of radiation (and its reaction on the charged particle) raises several conundrums about which technical papers are written even today. Tries to understand why an accelerated charge radiates in a simple, yet rigorous, manner.

3 illus, 5 ref

022369   Mani P;Suresh S (Physics Dep, Hindustan Univ, Padur-603 103, Email: mani_hce@yahoo.co.in) : FTIR and FTR spectral studies on 4-vinyl cyclohexene. Rasayan J Chem 2009, 2(2), 340-4.

FTIR and FTR spectra of 4-Vinyi Cyclohexene have been recorded in the regions 200 - 4000 cm^-1 and 30 -4000 cm^-1. The vibrational analysis has been carried out by assuming & symmetry. The observed frequencies were assigned to various modes of vibrations on the basis of intensity, frequencies from allied molecules and normal coordinate calculations. The potential energy distributions associated with normal modes are also reported here. The assignment of fundamental vibrational frequencies for 4-vinyl cyclohexene agree with the calculated frequencies.

2 illus, 1 table, 12 ref

022368   Mani P;Suresh S (Physics Dep, Hindustan Univ, Padur-603 103, Email: mani_hce@yahoo.co.in) : Vibrational spectra and normal coordinate analysis of acetic acid cyclohexyl ester. Rasayan J Chem 2009, 2(2), 307-11.

FTIR and FTR spectra of acetic acid cyclohexyl ester have been recorded in the regions 200 - 4000 cm^{-1 and 30 - 4000 cm-1. The vibrational analysis has been carried out by assuming C_s symmetry. The observed frequencies were assigned to various modes of vibrations on the basis of intensity, frequencies from allied molecules and normal coordinate calculations. The potential energy distribution associated with normal modes are also reported here. The assignment of fundamental vibrational frequencies for acetic acid cyclohexyl ester agree with the calculated frequencies.}

2 illus, 1 table, 9 ref

022367   Fernando J M R C;Senadeera G K R (NO, Institute of Fundamental Studies, Hantana Road, Kandy, Sri Lanka, Email: rsena@ifs.ac.lk) : Natural anthocyanins as photosensitizers for dye-sensitized solar devices. Curr Sci 2008, 95(5), 663-6.

Different natural pigments containing anthocyanins extracted from tropical flowers were studied as possible sensitizers for TiO2 by assembling dye-sensitized solar cells (DSCs). Photocurrent densities ranging from 1.1 to 5.4 mA cm^-2 were obtained with photovoltages ranging from 390 to 410 mV. The overall efficiency and fill factor of these cells varied from 0.2 to 1.1 and 53 to 64 respectively. Among the flower pigments studied, the extract from Hibiscus surattensis-HST (cultivated species/colour of the flower: magenta) gave the best photosensitized effect, which can be used as an environment-friendly, low-cost alternative system, especially for educational purposes.

3 illus, 1 table, 21 ref

021361   Yaremko Y (NO, Institute for Condensed Matter Physics, 1 Svientsitskii St., 79011 Lviv, Ukraine, Email: yar@ph.icmp.lviv.ua) : Two-body problem with retarded interactions and radiation reaction in classical electrodynamics. Indian J Phys 2008, 82(9), 1139-58.

Energy-momentum and angular momentum carried by electromagnetic field of two point-like charged particles are presented. Apart from usual contributions to the Noether quantities produced separately by particle 1 and particle 2, the conservation laws contain also the joint contribution due to the fields of both particles. So, radiative part of the energy-momentum contains, apart from usual integrals of Larmor terms, also the work done by Lorentz forces of point-like charges acting on one another. Interference part of radiated angular momentum is the sum of integrals of torque Lorentz forces over particles' world lines. Analysis of energy-momentum and angular momentum balance equations results the Lorentz-Dirac equation as an equation of motion for a pointed charge under the influence its own electromagnetic field as well as field produced by the other charge. The radiative component of mixed part of Maxwell energy-momentum density is given.

5 illus, 15 ref

021360   Whitney C K (Galilean Electrodynamics, Proceedings of the Natural Philosophy Alliance, 141 Rhinecliff Street, Arlington, MA 02476-7331, USA, Email: Galilean_Electrodynamics@comcast.net) : Expanding the realm of 'classical' electrodynamics. Indian J Phys 2008, 82(9), 1205-18.

Argues that a fairly straightforward revision of the current 'relativistic' theory of electrodynamics turns it into an essentially 'classical' theory that is capable of addressing both relativistic and 'quantum' phenomena. This kind of unification removes the many paradoxes of special relativity theory and the many mysteries of quantum mechanics, and restores electrodynamics to its deservedly fundamental place in the development of physical theory.

4 illus, 20 ref

021359   Vadamalar R;Mani P;Balakrishnan R (Physics Dep, Marudhar Kesari Jain College, Vaniyambadi) : Ultrasonic study of molecular interactions in binary mixtures of MMA with inert solvents. Int J Comp Applic 2008, 3(2), 161-7.

The densities and the ultrasonic velocity of binary mixtures for the various range of concentration (Methyl Methacrylate , anisole, tetrachloroethylene, trichloroethylene and 2 - chloroethanol) are measured at three different temperatures. From the experimental data's, the values of adiabatic compressibility, molar volume, free length and the available volume are calculated. Using the above data's, the nature of intermolecular interactions of the mixtures is studied.

2 tables, 16 ref

021358   Uttam K N;Singh R;Tandon P (Saha's Spectroscopy Laboratory, Physics Dep, Allahabad Univ, Allahabad-211 002, Email: kailash.uttam@rediffmail.com) : New band system of the MgBr molecule. Indian J Phys 2008, 82(11), 1523-7.

An electronic emission spectrum of magnesium monobromide molecule, excited in high temperature furnace, has been photographed in the λλ 3600 - 4050 Angustrum region at reciprocal linear dispersion of 7.3 A/mm. The study reveals the presence of a new band system, B - X in λλ 3600 - 3800 Angustrum region. About 16 single headed bands, degraded to higher wavelength side, have been attributed to this system. The vibrational analysis performed suggests that the system arises from the ground state involving transition B²Σ - X²Σ. The vibrational constants have been determined for the relevant states.

1 illus, 2 tables, 13 ref