Indian Journal of Pure and Applied Physics

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 ISSN: 0019-5596

CODEN: IJOPAU 44 (1) 1-80

VOLUME  44

NUMBER 1

JANUARY 2006


CONTENTS

Atomic and Molecular Physics

 

High-resolution electronic absorption spectrum of 2-fluoronaphthalene

5

R A Singh* & S N Thakur

 

Study of ion induced modification in Makrofol-KG polycarbonate by positron annihilation lifetime measurements

9

Rajesh Kumar & Rajendra Prasad*

 

Effect of preheating in biogenic shells Thermostimulated luminescence and FTIR study

13

V Ponnusamy, V Ramasamy* & K Anandalakshmi

 

Bonding parameter, phase parameter and Ni K-edge position studies of some Ni systems

20

Vinod K Singh

 

Freezing transition of two and three - dimensional classical fluids using double Yukawa potential

25

Y Pathania* & P K Ahluwalia

 

Physics of Gases, Plasmas and Electric Discharges

 

Propagation of soliton and its radiation in inhomogeneous discharge plasma

31

G C Das* & Karabi Devi

 

Condensed Matter: Structure, Mechanical and Thermal Properties

 

Study of resistivity of amorphous binary alloy using mode-coupling method

39

Punam Kumari , D N Jha* & P K Mishra

 

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

 

Electrical properties of La-modified strontium bismuth titanate

46

M Raghavender, G S Kumar & G Prasad*

 

Structural, optical, electrical and photovoltaic electrochemical studies of cobalt molybdate thin films

52

P K Pandey*, N S Bhave & R B Kharat

 

Electronic properties of CdS, CdSe and CdTe semiconductor binary alloys

59

A R Jivani, H J Trivedi, P N Gajjar & A R Jani*

 

Dielectric relaxation in glassy Se70Te30-xAgx

62

N Choudhary & A Kumar*

 

Interdisciplinary Physics and Related Areas of Science and Technology

 

Surface chemical etching behaviour of pristine and high energy Li ion irradiated kapton-H polyimide

66

Maneesha Garg, Anu Sharma & J K Quamara*

 

Realization of multi-function biquad filter using operational transconductance amplifier

71

K Kumar*, K Pal & G K Gupta

 

 

________

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

Indian Journal of Pure & Applied Physics
Vol. 44, January 2006, pp. 5-8

 

 

 

High-resolution electronic absorption spectrum of 2-fluoronaphthalene

R A Singh & S N Thakur*

Department of Physics, Dr H S Gour University, Sagar 470 003

*Department of Physics, Banaras Hindu University, Varanasi 221 005

Received 27 June 2005; revised 13 October 2005; accepted 10 November 2005

The vapour phase absorption spectrum 2-fluoronaphthalene has been recorded under high resolution. The vibronic bands involving ground and excited normal vibrations have been assigned on the basis of their rotational contours. Many new vibrational frequencies have been reported for the first time in the excited state of 2-fluoronaphthalene.

Keywords: Absorption spectrum, Vibrational bands, Fluoronaphthalene

IPC Code: G01J3/42

Indian Journal of Pure & Applied Physics

Vol. 44, January 2006, pp. 9-12

 

 

 

Study of ion induced modification in Makrofol-KG polycarbonate
by positron annihilation lifetime measurements

Rajesh Kumar & Rajendra Prasad

Department of Applied Physics, Z H College of Engineering & Technology, Aligarh Muslim University, Aligarh 202 002

E-mail: drrajesh04@rediffmail.com

Received 27 June 2005; accepted 17 November 2005

Latent ion tracks produced in the polymers due to the damage produced by the passage of swift heavy ions contain amorphous material with highest degree of disorder, changing the free volume properties, which have strong correlation with the macroscopic properties of the material. Positron Annihilation Lifetime Spectroscopy (PALS) is a non-destructive and non-interfering probe, having high detection efficiency for free volume hole properties and provides direct information about the dimension, content and hole size distribution of free volume in polymers. The effect of irradiation of Si8+ 100 MeV ions on Makrofol-KG polycarbonate by PALS is reported here. From the ortho positronium (o-Ps) lifetime, mean free volume, radius and average free volume have been obtained.

Keywords: Makrofol-KG polycarbonate, Si8+ ion irradiation, Positron lifetime, Free volume, Ion beam modification

IPC Code: G08G64/00

Indian Journal of Pure & Applied Physics

Vol. 44, January 2006, pp. 13-19

 

 

 

 

Effect of preheating in biogenic shellsThermostimulated luminescence and FTIR study

V Ponnusamy, V Ramasamy & K Anandalakshmi

Department of Physics, Annamalai University, Annamalainagar 608 002, Tamil Nadu
E-mail: srsaranram@rediffmail.com

Received 3 May 2005; accepted 31 August 2005

The thermostimulated luminescence (TSL) and Fourier transform infrared (FTIR) measurements were carried out for ten biogenic shells at room temperature (RT) and various temperatures in the range 200-800C, at an interval of 50C, for
1 hr duration. The glow curves of unannealed sample show only one peak at 330
C. The sample irradiated with a gamma dose of 500 Gy shows an additional peak at 130C, when recorded with linear heating rate of 10C/s. The annealed sample also shows the same trend. Annealing treatment above 250C increases the sensitivity of 130C TSL peak. A sudden reduction in TSL sensitivity at 500C is observed. At this temperature (500C), FTIR study shows structural disorderedness or phase transition and formation of new structure in the major mineral content. On the other hand, preheating at 700C caused a collapse in the TSL sensitivity.

Keywords: Thermal treatment, Aragonite, Biogenic shells, Calcite, Glow curve characteristics, FTIR

IPC Code: G01J 3/28

Indian Journal of Pure & Applied Physics

Vol. 44, January 2006, pp. 20-24

 

 

 

 

Bonding parameter, phase parameter and Ni K-edge position studies of
some Ni systems

Vinod K Singh

Department of Applied Physics, Indian School of Mines, Dhanbad 826 004, Jharkhand

Email: vksingh@perl.ism.ac.in

Received 17 November 2004; revised 17 August 2005; accepted 9 September 2005

Extended X-ray absorption fine structure (EXAFS) phase shift studies of some nickel compounds have been carried out and the values of bonding parameter a1 and phase parameter b1 are evaluated by graphical method. a1 is then correlated with nearest neighbour distance and ionicity of the corresponding systems. It has been observed that the bonding parameter a1 decreases as bond distance decreases except in Ni3(PO4)2.XH2O and NiCl2.6H2O and decreases with increase of the ionicity except for NiBr2. The phase parameter b1 has been correlated with oxygen atoms present in a system. The nickel K-edge position in the systems under study has been correlated with ionicity. No good relation has been observed between ionicity and edge position. This has been attributed to different structure and coordination number of a system.

Keywords: EXAFS, XAFS, K-edge X-ray absorption spectra

IPC Code: G01J3/42

Indian Journal of Pure & Applied Physics

Vol. 44, January 2006, pp. 25-30

 

 

 

 

Freezing transition of two- and three-dimensional classical fluids using

double Yukawa potential

 

Y Pathania & P K Ahluwalia

Physics Department, Himachal Pradesh University, Shimla 171 005

Received 26 July 2004; revised 26 May 2005; accepted 13 September 2005

Employing the techniques of molecular dynamics computer simulation, the onset of the freezing region of two and three-dimensional classical fluids interacting via Double Yukawa potential have been investigated. The radial distribution function g(r) for unique, qualitative and quantitative structural characteristics associated with the onset of freezing and for the validity of a universal freezing criterion has been studied. We have compared our results with those of Lennard Jones, when parameters occurring in Double Yukawa potential are chosen to fit the Lennard Jones potential. Later, the attractive and repulsive parameters of Double Yukawa potential have been varied to study the effect of attractive and repulsive part of the potential separately on the freezing criterion.

Keywords: Freezing transition, Classical fluids, Double Yukawa potential, Molecular dynamics computer simulation

IPC Code: G06N3/10, F15D

 

Indian Journal of Pure & Applied Physics

Vol. 44, January 2006, pp. 31-38

 

 

 

Propagation of soliton and its radiation in inhomogeneous discharge plasma

G C Das & Karabi Devi

Mathematical Sciences Division, Institute of Advanced Study in Science and Technology, Paschim Boragaon,
Guwahati 781 035, Assam

Received 4 November 2004; revised 11 April 2005; accepted 20 October 2005

The salient features of soliton dynamics generated with the interaction of negative ions in inhomogeneous plasma has been studied through the derivation of modified Korteweg-de Vries (mK-dV) equation. Because of the complexity of plasma non-linear wave equation, the usual steady state method found to face difficulty to yield the soliton solution. The new approach known to be sine-cosine method shows the success on yielding soliton propagation along with a precursor of growing mode. The study has been furthered with higher order non-linear effect resulted on the inherent behaviour of precursor and relates the observations with actual experimental observations. The study also shows that the soliton along with the precursor, due to the interaction of negative ions, might collapse expecting a source of high-energy with radiation-like called soliton radiation. These observations could be an advanced knowledge on soliton dynamics in Townsend discharge plasma and thus might be of interest to yield soliton propagation along with precursor in laboratory and space plasmas.

Keywords: K-dV solitons, Inhomogeneous plasma, Sine-cosine method, Soliton radiation

IPC Code: H05H

 

 

Indian Journal of Pure & Applied Physics

Vol. 44, January 2006, pp. 39-45

 

 

 

Study of resistivity of amorphous binary alloy using mode-coupling method

 

Punam Kumari1, D N Jha1 & P K Mishra2

1Department of Physics, TNB College, Bhagalpur

2University Department of Physics, TMBU, Bhagalpur

Received 10 October 2005;accepted 16 November 2005

The mode-coupling approximation in electron-phonon interaction, which has opened a new approach for the description of electrical transport in high resistor conductors, liquid transition metals and strongly disordered systems has been extended to solid amorphous binary alloys. A simplified expression for electrical conductivity of amorphous alloys has been obtained in terms of current relaxation kernel and density relaxation kernel by adding electron-phonon coupling term in the Hamiltonian. The structure factor is allowed to vary with temperature and the product of the coupling coefficient with the static structure factor has been replaced by the T-matrix in Born approximation as in extended Ziman-Evans model. A modified formula purporting variation of packing fraction with temperature and concentration has been used to derive the TCR. The same form of packing fraction has been used for structure factors as well. Also the thermoelectric power has been calculated to verify Mooij law and study its variation with temperature. The case study of NixP1-x alloy with x=0.85 and 0.75 has been undertaken and results tested for valence values z =1.03, 1.10, 1.21 at x=.85 and z =1.28, 1.33 at x=.75 with atomic volumes 75.5, 76.60 au. It has been found that the model satisfies the experimental results both qualitatively and quantitatively.

Keywords: Amorphous binary alloy, Mode-coupling method, Electron-phonon interaction

IPC Code: G01R27/02

Indian Journal of Pure & Applied Physics

Vol. 44, January 2006, pp. 46-51

 

 

 

 

Electrical properties of La-modified strontium bismuth titanate

M Raghavender, G S Kumar & G Prasad*

Materials Research Laboratory, Department of Physics, Osmania University, Hyderabad

Received 20 May 2005 ; accepted 6 October 2005

Bismuth ion in four layered strontium bismuth titanate (SBT), a compound of Aurivillius family, is partially replaced with La3+ in the place of Bi3+ to synthesize SrBi (4-x)LaxTi4O15, with x = 0.25, 0.50, 0.75. The ceramic powders were prepared using chemical route. The temperature dependence of the dielectric and impedance properties was studied over a wide frequency range. The dielectric properties showed interesting changes in the transition temperatures. These changes are correlated with the distortion that sets in the samples due to the incorporation of lanthanum. The octahedra and square pyramidal lattice distortion of the perovskite layers in ABO3 is calculated from lattice parameters. Dielectric transition temperatures are correlated with displacement of A-site ions with respect to octahedral center.

Keywords: Dielectric properties, Impedance, Strontium bismuth titanate, Perovskite materials

IPC Code: H01G 7/06

Indian Journal of Pure & Applied Physics

Vol. 44, January 2006, pp. 52-58

 

 

 

 

 

Structural, optical, electrical and photovoltaic electrochemical studies of cobalt molybdate thin films

P K Pandey*, N S Bhave & R B Kharat

Department of Chemistry, Nagpur University, Nagpur 440 033
Email: pandeykp2003@yahoo.co.uk

Received 25 May 2005; revised 25 October 2005; accepted 10 November 2005

The deposition of cobalt molybdate (CoMoO4) thin film by spray pyrolysis (SP) process, using its ammoniacal solution as precursor, has been presented. The growth of the film takes place by pyrolytic decomposition of the spraying precursor solution onto the preheated glass substrates. X-ray diffraction (XRD) studies confirm the microcrystalline, single-phase nature of the sintered thin films. Scanning electron microscope (SEM) images clearly show the aggregate of crystallites of dimensions 1-5 mm. The optical absorption studies of the sintered thin films in the wavelength range 350 - 850 nm show direct as well as indirect optical transitions in the material. The direct and indirect band gap values found to be 1.75 and 1.40 Ev, respectively. The films are semiconducting in nature and highly resistive at room temperature as evident from their dc electrical conductivity measurements obtained by the two point probe method in the temperature range 300 - 500 K. Plot of log(σ) versus 1/T clearly indicates a break in the curve corresponding to the temperature 345 K. The thin films of CoMoO4 deposited on FTO coated conducting glass substrate were sintered in hydrogen atmosphere to be used as photoanode in photovoltaic electrochemical (PVEC) cell. The PVEC cell configuration is: CoMoO4 | Ce4+, Ce3+ | Pt; 0.1 M in 0.1 N H2SO4. The PVEC characterization reveals the fill factor and power conversion efficiency to be 0.431 and 1.20%, respectively. The flat band potential has been found to be 0.32 V versus Standard calomel electrode (SCE).

Keywords: Cobalt molybdate thin films, Spray pyrolysis, Optical absorption, dc electrical conductivity

IPC Code: H01C17/1075, G01R

Indian Journal of Pure & Applied Physics

Vol. 43, January 2006, pp. 59-61

 

 

 

 

Electronic properties of CdS, CdSe and CdTe semiconductor binary alloys

A R Jivani, H J Trivedi, P N Gajjar & A R Jani

Department of Physics, Sardar Patel University, Vallabh Vidyanagar, 388 120, Gujarat

Received 26 July 2005; accepted 2 November 2005

The higher-order perturbation theory based on pseudopotential is used to calculate total energy, band gap at Jones-zone face and bulk modulus of CdS, CdSe and CdTe binary semiconductor compounds. The covalent correction term, which is approximately equal to third and fourth-order perturbation energy, is used in the present study. The ratio of covalent bond correction energy to second-order perturbation energy is about 15% and hence it is essential to study the electronic properties of semiconductor materials. Present theoretical results are found better than other available theoretical findings and good agreements of present finding of total energy, band gap at Jones-zone face and bulk modulus with the experimental data are achieved.

Keywords: Higher-order perturbation theory, Pseudopotential, Band gap, Binary semiconductor compound

IPC Code:C30B

Indian Journal of Pure & Applied Physics

Vol. 44, January 2006, pp. 62-65

 

 

 

Dielectric relaxation in glassy Se70Te30-xAgx

N Choudhary & A Kumar*

Department of Physics, Harcourt Butler Technological Institute, Kanpur 208 002

Received 29 September 2004; revised 24 May 2005; accepted 25 May 2005

Temperature dependence of dielectric constant (e') and dielectric loss (e") are studied in glassy Se70Te30-xAgx where x is varied from 0 to 10 in the frequency range 1 to 10 kHz and temperature range 300-350 K. The results indicate that the dielectric dispersion exists in the above frequency and temperature range. Loss peaks in e" versus T curve could be observed in ternary Se70Te30-xAgx alloys. However, such loss peaks could not be observed in binary Se70Te30 alloy, which indicates that Ag incorporation in binary system, is responsible for such behaviour. This is explained in terms of [(D-) (Ag+)] dipoles which otherwise were not present in the undoped samples.

Keywords: Chalcogenide glasses, Dielectric relaxation, Ternary alloys

IPC Code: G01R27/26

Indian Journal of Pure & Applied Physics

Vol. 44, January 2006, pp. 66-70

 

 

 

Surface chemical etching behaviour of pristine and high energy Li ion
irradiated kapton-H polyimide

 

Maneesha Garg, Anu Sharma & J K Quamara*

Department of Applied Physics, National Institute of Technology, Kurukshetra 136 119

Received 9 June 2005; revised 25 October 2005; accepted 14 November 2005

High energy heavy ion irradiation effect on surface chemical etching behaviour of kapton-H polyimide has been studied using NaOH (40C) and NaOCl (55C) as etchants. The samples have been irradiated with 50 MeV Li ions (fluence 105 ions/cm2 at Pelletron Facility, Nuclear Science Center, New Delhi). The etching behaviour is non-linear in NaOH for both pristine and irradiated samples. There is an enhancement in the etching rate in irradiated samples for both NaOH and NaOCl etchants. The etching mechanism of pristine and irradiated kapton-H polyimide with NaOCl and NaOH has been investigated. In irradiated samples the demerization of carbonyl groups, breaking of imide linkages and increase in crystallinity have been held responsible for the change in the etching behaviour. The bulk activation energy of pristine and irradiated samples for NaOH (0.38 and 0.30 eV) and NaOCl (1.6 and 1.3 eV) has been estimated. High temperature vacuum annealed samples when etched with NaOH show swelling instead of etching, which is due to a unique type of gel formation taking place on the surface.

Keywords: Surface chemical etching, High energy heavy ion irradiation, Kapton-H polyimide

IPC Code: C08J3/28

 

Indian Journal of Pure & Applied Physics

Vol. 44, January 2006, pp. 71-74

 

 

Realization of multi-function biquad filter using
operational transconductance amplifier

K Kumar, K Pal* & G K Gupta

Department of Physics, DBS College, Dehradun, Uttranchal

*Department of Earthquake Engineering, IIT Roorkee, Roorkee

Email: kushal_kairi@yahoo.co.in,kiratfeq@iitr.ernet.in

Received 28 January 2005; revised 22 August 2005; accepted 31 October 2005

A configuration of voltage mode (VM) multi-function biquad filters (MBF) is presented in this paper. The configuration (MBF) is implemented by using two OTAs (one dual output and other single output) and two capacitors. It realises all standard filtering functions i.e. low pass (LP), high pass (HP), band pass (BP), notch and all pass (AP). This configuration (MBF) can also be constructed using a single OTA, two capacitors and one resistor. It employs minimum of active and passive components and provides an attractive feature in case of BP filter that it can be designed for high Q. In addition, the circuit enjoy low sensitivity performance. The experimental results that confirm the validity of the circuit are included.

Keywords: Voltage mode, Multi-function filter, Operational transconductance amplifier, Active Filter

IPC Code: H03H