Indian Journal of Pure and Applied Physics

 

ISSN: 0019-5596   CODEN:IJOPAU 41(3) 157-248(2003)
VOLUME 41

   NUMBER 3   

 MARCH  2003

 

CONTENTS

 

 

Atomic and Molecular Physics

Vibrational spectra and analysis on the molecule of potassium pentaborate crystal (KB5)

V Joseph, V Santhanam, S Gunasekaran* P Sagayaraj & S Ponnusamy

 

161

Electromagnetism, Optics, Acoustics, Heat Transfer, Classical Mechanics and Fluid Dynamics

Numerical solution of hydromagnetic unsteady free convection flow past an infinite porous state

Atul Kumar Singh

 

167

Condensed Matter: Structure, Mechanical and Thermal Properties

Calorimetric measurements of Te-Bi-Se glasses with variation in Bi content

Manish Saxena*, Nikhil Rastogi, Animesh Agarwal & P K Bhatnagar

 

171

Field emission in diamond-like carbon films grown by various techniques

O S Panwar*, Sushil Kumar, S S Rajput, Rajnish Sharma & R Bhattacharyya

175

Influence of inhibition of citric acid and lemon juice to the growth of calcium hydrogen phosphate
dihydrate urinary crystals

Vimal S Joshi & Mihir J Joshi*

183

Acoustics and thermodynamics of alcoholic solution of calcium nitrate

Narayani Prasad* & A A Daudi

193

Crystallization kinetics of Fe78 Bi13Si9 metallic glass before and after high-energy heavy ion irradiation

Rohit Jain, N S Saxena* & Deepika Bhandari

198

Condensed Matter: Electronic Structure, Electrical, Magnetic and Optical Properties

Fluorescence properties of Nd3+ doped B2O3-P2O5-Li2SO4 glass

V Aruna* , N Sooraj Hussain & N V V  Prasad

 

206

Anomalous resistive transition and frequency dependent dielectric constant of Zn1-x MxO[M=Li(Mg, Ba)] system

M K R Khan*, M Mozibur Rahman, S Javed Mia & M Shahajahan


211

Non-linear cross-talk analysis in fiber Raman amplifiers

V K Chaubey*, V Jagannathan, R Rajagopalan & R Seshadrinathan

217

Modeling, characterization and optimization of tri-step doped InAlAs/InGaAs heterostrucure, InP based HEMT for microwave frequency applications

Ritesh Gupta, Mridula Gupta & R S Gupta*

223

X-ray, K-absorption near edge structural study of some copper(II) complexes with amino acids as ligands

A Mishra, M Mahajan & K K Johar*

232

Lb2 satellites in X-ray emission spectra of elements 75Re, 77Ir and 79Au

S Poonia & S N Soni

236

News Scan

Emerging technology of quantum dot lasers

Poonam  Bhat

 

242

*The corresponding author has been indicated by (*) mark in case of papers with more than one author

 

 

 

Indian Journal of Pure & Applied Physics

Vol. 41, March  2003, pp. 161-166

 

Vibrational spectra and analysis on the molecule of potassium pentaborate crystal (KB5)

V Joseph*, V Santhanam#, S Gunasekaran†, P Sagayaraj* & S Ponnusamy‡

*Department of Physics, Loyola College, Chennai 600 034

 

Received 15 May 2002; revised 28 August 2002; accepted 26 November 2002

 

 

Potassium pentaborate (KB5) crystals have been grown by solution growth technique. A structural investigation on the KB5 crystal is made, using FTIR and laser Raman spectra. The molecular structure of KB5 belongs to C2V symmetry considering the hydroxyl group as point mass. The total number of normal modes of vibration is 39 and are distributed as Gvib = 14A1 + 5A2 + 10B1 + 10B2. A normal coordinate analysis has been carried out with an orthonormal set of symmetry coordinates following Wilson F-G matrix method. The potential constants evaluated for this molecule are found to be in good agreement with literature, thereby, confirming the vibrational assignments. To check whether the chosen set of vibrational frequencies contributes maximum to the potential energy associated with the normal coordinates of the molecule, the potential energy distribution has been evaluated. Further, the thermogravimetric analysis (TGA) confirms the decomposition of KB5 taking place in two stages. The differential scanning calorimetry (DSC) curve of KB5 crystals has been recorded in the temperature range 50-580 °C. The phase transition temperature and enthalpies of KB5 were measured and the results are discussed.

 

 

 

Indian Journal of Pure & Applied Physics

Vol. 41, March 2003, pp. 167-170

 

 

Numerical solution of hydromagnetic unsteady
free convection flow past an infinite porous plate

Atul Kumar Singh

Department of Mathematics, VSSD College, Kanpur 208 002

 

Received 1 March 2002; revised 12 November 2002; accepted 28 December 2002

 

 

Unsteady free convection flow of an incompressible, electrically conducting, viscous fluid past an infinite vertical porous flat-plate under the influence of uniform magnetic field, applied normal to the flow, has been studied by finite difference method. The uniform suction is considered normal to the plate. The results for the velocity distribution, the temperature distribution and the skin-friction have been investigated and discussed for different values of the parameters encountered in the equations.

 

 

 

Indian J Pure & Applied Physics

Vol. 41, March  2003, pp. 171-174

 

 

Calorimetric measurements on Te-Bi-Se glasses with
variation in Bi content

Manish Saxena, Nikhil Rastogi, Animesh Agarwal & P K Bhatnagar*

Department of Sciences & Humanities, Moradabad Institute of Technology, Ram Ganga Vihar, Phase II, Moradabad 244 001

*Department of Electronic Science, University of Delhi, South Campus, New Delhi 110 021

 

Received 12 July 2002; revised 24 October 2002; accepted 27 January 2003

 

Alloys of Te-Bi-Se glass system, obtained by rapid quenching technique, have been characterized by calorimetric measurements and differential thermal analysis for different heating rates. Variation in two important parameters, namely, glass transition temperature Tg and glass forming ability Kgl have been studied with variation in Bi content at various heating rates. By analyzing the results, it has been seen that, with the increase in Bi content, the glass forming ability Kgl decreases. However, with the increase in heating rates, the glass transition temperature Tg is found to increase. This analysis helps in finding the suitability of an alloy to be used in phase transition optical memories/switches. The results have been analyzed using Kissinger’s equation for non-isothermal crystallization of materials.

 

 

 

 

Indian Journal of Pure & Applied Physics

Vol. 41, March 2003, pp. 175-182

 

 

Field-emission in diamond-like carbon films grown by
various techniques

O S Panwar,*Sushil Kumar, S S Rajput, Rajnish Sharma & R Bhattacharyya

Thin Film Technology Group, National Physical Laboratory, Dr KS Krishnan Road, New Delhi ll0 0l2

 

Received 22 August 2002; revised 30 October 2002; accepted 1 January 2003

 

 

The field-emission measurements from ~0.5 µm thick hydrogenated amorphous carbon (diamond-like carbon) films grown by a variety of easily implementable plasma enhanced chemical vapour deposition (PECVD) based techniques and also by a method that uses a saddle-field fast atom beam source, have been reported. Field-emission behaviour in these materials has been discussed in the light of residual stress, hardness, optical bandgap, and characteristic energy of band tails (Urbach energy). Onset emission fields as low as~ 6V/µm, together with low residual stress of 0.25 GPa, hardness of 17.5 GPa, optical bandgap of 1.5 eV and Urbach energy of 165 meV, have been obtained in diamond-like carbon films grown by pulsed-PECVD at 13.56 MHz. DLC films of comparable quality could also be grown using a saddle-field fast atom beam source, which operates on modest dc power supply and with no heated filaments or magnets.

 

 

 

Indian Journal of Pure & Applied Physics

Vol. 41, March 2003, pp. 183-192

 

 

Influence of inhibition of citric acid and lemon juice to the growth of calcium hydrogen phosphate dihydrate urinary crystals

Vimal S Joshi* & Mihir J Joshi

Solid State Physics and Materials Science Laboratory, Department of Physics, Saurashtra University, Rajkot 360 005

[E–mail: mshilp24@hotmail.com]

 

Received 2 July 2002; revised 23 October 2002; accepted 23 January 2003

 

 

Calcium hydrogen phosphate dihydrate (CHPD) crystal is a well-known urinary crystal. Calcium phosphate is present in urinary calculi (stones) as either apatite or brushite. Crystals of calcium hydrogen phosphate dihydrate were grown by single diffusion gel growth technique in silica gels. The supernatant solution containing combinations of constituents, like only calcium chloride, calcium chloride + citric acid; calcium chloride + lemon juice; calcium chloride + lemon juice + artificial reference urine (ARU) and calcium chloride + lemon juice + natural urine, were used to study the growth and inhibition of CHPD crystals. The growth velocity measurements indicated maximum inhibition in case of calcium chloride + lemon juice + natural urine containing solution. SEM (scanning electron microscope) and FTIR (Fourier transform infrared) spectroscopy were used to study the crystals. The results are discussed in terms of citrate inhibition and inhibition due to natural urine.

 

 

 

 

Indian Journal of Pure & Applied Physics

Vol. 41, March 2003, pp. 193-197

 

 

Acoustics and thermodynamics of alcoholic solution of
calcium nitrate

Narayani Prasad & A A Daudi

Department of Biochemistry, Faculty of Basic Sciences & Humanities, Rajendra Agriculture University, Pusa, Samastipur, Bihar

 

Received 21 March 2002; revised 6 August 2002, accepted 2 January 2003

 

 

Apparent partial molal volumes and compressibilities of calcium nitrate  in six alcohols have been determined at 296.15 K from precise density and ultrasound velocity measurements. They have been related with each other, as well as with free energy of the solutions.

 

 

 

 

Indian Journal of Pure & Applied Physics

Vol. 41, March 2003, pp. 198-205

 

 

Crystallization kinetics of Fe78B13Si9 metallic glass before and
after high-energy heavy ion irradiation

Rohit Jain, N S Saxena & Deepika Bhandari

Condensed Matter Physics Laboratory, Department of Physics, University of Rajasthan, Jaipur 302 004

 

Received 19 June 2002; accepted 30 November 2002

 

 

Crystallization kinetics of virgin and irradiated (at three different fluences with high energy heavy ion; Ni11+ of (150 MeV) specimens of Fe78B13Si9 glass has been studied using Differential Scanning Calorimetry (DSC) under non-isothermal condition. Only one set of geometry has been used for irradiation at different fluences. It has been found that, the crystallization process is completed in two phases. The DSC data have been analyzed in terms of kinetic parameters, viz. activation energy (Ec), Avrami exponent (n), dimensionality of growth (m) and frequency factor (Ko) using two different theoretical models. The lower activation energy in case of second crystallization occurring at higher temperature indicates the easier nucleation of second phase, which is termed Fe2B bct phase. The abnormally high value of Avrami exponent indicates very high nucleation rate during second crystallization.

 

 

 

Indian Journal of Pure & Applied Physics

Vol. 41, March 2003, pp. 206-210

 

 

Fluorescence properties of Nd3+ doped B2O3-P2O5-Li2SO4 glass

V Aruna, N Sooraj Hussain & N V V Prasad

Department of Physics, Sri Venkateswara University, Tirupati 517 502

 

Received 2 September 2002; accepted 6 January 2003

 

 

The production of neodymium glass in the chemical composition of 44.75 B2O3-44.75P2O5-10Li2SO4 has been reported. An intense up-converted violet colour emission has been observed upon excitation with a yellow light. The violet colour up-conversion process has been explained by an energy level scheme. By correlating the measured fluorescence life-time results with the absorption data, the quantum efficiency (h=44%) of the optical material has been evaluated from the application of Judd-Ofelt theory.

 

 

 

Indian Journal of Pure & Applied Physics

Vol. 41, March 2003, pp. 211-216

 

 

Anomalous resistive transition and frequency dependent dielectric constant of Zn1-xMxO [M=Li (Mg, Ba)] system

M K R Khan, M Mozibur Rahman, S Javed Mia & M Shahajahan

Department of Physics, University of Rajshahi, Rajshahi 6205, Bangladesh

[E-mail:ykrkhan@yahoo.com]

 

Received 17 June 2002; revised 13 January 2003; accepted 27 January 2003

 

 

The II-VI materials of Zn1-xMxO have been synthesized by solid-state reaction method and their structural, electrical and dielectric properties studied. The lattice parameters of these materials are found to be consistent with the reported values. The dielectric constant measured at different five frequencies agrees well with the published values and found to be maximum for doping concentration x = 0.2, at all frequencies. A dc resistive anomaly was found for all samples at a certain temperature called transition temperature (Td-s) from dielectric to semiconducting state, which depends on the concentration and nature of the dopant atoms in ZnO.

 

 

 

Indian Journal of Pure & Applied Physics

Vol. 41, March 2003, pp. 217-222

 

 

Non-linear cross-talk analysis in fiber Raman amplifiers

V K Chaubey, V Jagannathan, R Rajagopalan & R Seshadrinathan

Electrical and Electronics Engineering Department, Birla Institute of Technology and Science, Pilani, 333 031

 

Received 5 June 2002; revised 20 September 2002; accepted 22 January 2003

 

 

Optical non-linearities limit the optical power and information capacity of light-wave systems. These non-linearities introduce different types of frequency and phase distortions, which lead to cross-talk. Various non-linear effects that affect Raman amplification have been discussed and an evaluation of the cross-talk induced due to these effects, has been  presented. The maximum input power that can be transmitted in a WDM system without degrading its performance has also been evaluated.

 

 

 

Indian Journal of Pure & Applied Physics

Vol. 41, March 2003, pp. 223-231

 

 

Modeling, characterization and optimization of tri-step doped InAlAs/InGaAs heterostructure, InP based HEMT
for microwave frequency applications

Ritesh Gupta, Mridula Gupta & R S Gupta

Semiconductor Device Research Laboratory, Department of Electronic Science,

University of Delhi South Campus, New Delhi 110 021

 

Received 20 June 2002; accepted 29 November 2002

 

 

A new analytical model for tri-step doped InAlAs/InGaAs heterostructure InP based HEMT has been proposed in this paper. Maximum sheet carrier density has been formulated considering the limitation arising from the doping-thickness product. A comparison is made between conventional pulsed doped structure and equivalent tri-step doped structures to validate the model. The conventional pulsed doped device is also optimized for higher sheet carrier concentration/effective parallel conduction voltage/transconductance/cut-off frequency by varying the Schottky layer thickness for identical carriers using equivalent tri–step doped structure.

 

 

 

 

Indian Journal of Pure & Applied Physics

Vol. 41, March 2003, pp. 232-235

 

 

X-ray, K-absorption near edge structural study of some
copper(II) complexes with amino acids as ligands

A Mishra

 School of Physics, Devi Ahilya University, Indore 452 001

and

M Mahajan & K K Johar

Department of Physics, Government PG College, Khargone 451 001

 

Received 29 May 2002, revised 18 December 2002, accepted 28 January 2003

 

 

X-ray, K-absorption spectra of five copper (II) complexes have been recorded using a 0.04 m radius Cauchois type, curved crystal spectrograph. Parameters like, chemical shift, edge width, effective nuclear charge, percentage covalency, shift in principal absorption maxima etc. have been calculated and used to interpret the structural details of the complexes. Wiener indices have also been calculated for the complexes.

 

 

 

Indian Journal of Pure & Applied Physics

Vol. 41, March 2003, pp. 236-241

 

 

Lb2 satellites in X-ray emission spectra of elements
75Re, 77Ir and 79Au

S Poonia*

Division of Natural Resources and Management, Central Arid Zone Research Institute, Jodhpur, Rajasthan 342 003

and

S N Soni

X-Ray Laboratory, Physics Department, Jai Narain Vyas University, Jodhpur 342 005

 

Received 7 October 2002; revised 20 December 2002; accepted

 

 

The satellite spectra arising due to L3Mx-MxN4,5 (x ş 1-5) transition array in X-ray emission spectra of 75Re, 77Ir and 79Au, have been calculated, using available Hartree–Fock–Slater (HFS) data on K-LM and L-MN Auger transition energies. The agreement between the calculated and measured energies, between calculated and measured separations in energies and the consideration of the relative probabilities of all the L3Mx-MxN4,5 transitions have been used as the basis for deciding the origin of the satellites. It has been established that, two satellites observed in the Lb2 region of the X-ray spectra of the elements with Z=75 to 79, named b2I and b2II in order of increasing energy are mainly emitted by L3M4,5-M4,5N4,5 transitions. The satellite b2I has been assigned to the super-position of the transitions 3F4-3G5 and 3F4-3D3, contributing in order of decreasing intensity, and the line b2II, has been assigned to mainly the 1F3-1G4 and 3P0-3D1 transitions. The possible contributions of other transitions of the L3Mx-MxN4,5 (x ş 1-5) array having appreciable intensities have also been discussed.

 

 

 

Indian Journal of Pure & Applied Physics

Vol. 41, March 2003, pp. 242-242

 

 

NEWS SCAN

 

Emerging technology of quantum dot lasers

 

 

Laser light is very different from normal light. It is monochromatic, coherent, directional, very strong and concentrated. Lasers emit radiation at a single wavelength. Therefore, the applications which require many wavelengths need several lasers. Quantum wells can be engineered to emit different wavelengths. A quantum well is a layer of semiconducting material embedded in a semiconductor with a larger bandgap. The charge carriers - the electrons can then be trapped in a well where these can occupy certain quantised energy states, similar to the electrons in an atom. Semiconductor lasers play a major role in many technological products like compact disk players, optical data storage, a bar code readers , laser printers and optical communication.(C Gmachi et al.,415,Nature,883).