††† Indian Journal of Pure and Applied Physics

 

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VOLUME 40††††††††††††††††††††††††††††††††††††††††††††††††††† NUMBER 2††††††††† ††††††††††††††††††††††††††††††††††††††††FEBRUARY2002

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CONTENTS

 

Nuclear Physics

Theoretical prediction of magnetic octupole strength and form factor in rare earth nuclei using two rotor

††††† model

A M Hegazi

 

 

79

Atomic and MolecularPhysics

Vibrational studies of gel grown antimony thiourea chloride and bismuth thiourea chloride crystals

†††† A Jayarama, S Govinda Bhat & S M Dharmaprakash*

 

85

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

Absorption, excitation and emission spectra of direct yellow 8 in aqueous solutions

R M P Jaiswal*, N Singh, Neena Jaggi & Manoj Gir

 

89

Condensed Matter: Structure, Mechanical and Thermal Properties

Effect of basic temperature gradients on Marangoni convection in ferromagnetic fluids

††††† N Rudraiah*, I S Shivakumara & C E Nanjundappa

 

95

Study of influence of pre-heat treatment on thermoluminescence glow curve pattern and related trapping parameters of technologically important synthetic quartz specimen

††††† Y D Kale, Y H Gandhi* & T R Joshi

 

107

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

Application of light scattering for the determination of molecular parameters: Polystyrene balls

††††† Ritesh Kumar Dubey, R K Pandey & D N Tripathi*

 

111

Flourescence studies of biphenyl doped by pyrene and perylene

††††† S R Pujari*, S A Jadhav, P N Bhosale, P M R Rao & S R Patil

115

Structural and optical properties of monolithic silica-gel glasses containing Nd+3 using two different precursors TEOS and TMOS prepared by sol-gel technique

†† †††I K Battisha

 

122

Development of fibre optic pH meter based on colorimetric principle

††††† A L Chuadhari & A D Shaligram*

132

Interdisciplinary Physics and Related Areas of Science and Technology

Measurement of half-life of iridium-192 (HDR brachytherapy) by clinical dosimeters

††††† Alok Kumar* & Sudama Singh

 

137

Geophysics, Astronomy and Astrophysics

Study of electric field, Aitken nuclei, gaseous concentrations and ionic conditions in contrasting environment

††††† S S Kandalgaonkar*, M I R Tinmaker, M K Kulkarni & Asha Nath

 

141

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

 

 

Indian Journal of Pure & Applied Physics

Vol. 40, February2002, pp. 79-84

Theoretical prediction of magnetic octupole strength and form factor in rare earth nuclei using two rotor model

A M Hegazi

 

Collective magnetic octupole transitions for the Jp =3+ member of the low lying Kp =1+band are investigated in the framework of the two-rotor-model. The systematic study, carried out for deformed nuclei within a large range of the deformation parameter. The form factor of the orbital collective M3 transitions has also been calculated in plane wave Born approximation using Fermi density distribution. The theoretical calculations are simple and can be easily computed numerically.

Indian Journal of Pure & Applied Physics

Vol. 40, February 2002, pp. 85-88

Vibrational studies of gel grown antimony thiourea chloride and bismuth thiourea chloride crystals

A Jayarama , S Govinda Bhat & S M Dharmaprakash

Single crystals of antimony thiourea chloride (ATC) and bismuth thiourea chloride (BTC) have been grown in gels at ambient temperature using a controlled chemical reaction method. The laser Raman and FTIR spectra of the gel grown ATC and BTC crystals have been recorded. The presence of thiourea ion, water molecules and normal mode vibrational frequencies are identified and discussed. The basic ideas regarding the normal modes of vibration, selection rules for Raman and IR spectra and hydrogen-bonding effect are considered in brief. Molecules of water of crystallization are weakly bonded in antimony thiourea chloride crystal and do not take part in hydrogen bond formation.

 

Indian Journal of Pure & Applied Physics

Vol. 40, February2002, pp. 89-94

Absorption, excitation and emission spectra of

direct yellow 8 in aqueous solutions

R M P Jaiswal, N Singh, Neena Jaggi* & Manoj Gir

 

The absorption, excitation and emission spectra of direct yellow 8 [C24H19N4NaO5S2] have been recorded in aqueous solutions of concentrations between 10-4 and 10-6 Ml-1. This has led to the determination of optimum concentrations for the absorption and emission spectra of the compound. Three absorption peaks at l ~ 395, 287 and 226 nm at the concentration 10-5 Ml-1 have been observed and assigned to 1W ¨ 1A (p*¨ n), 1Lb ¨ 1A (secondary p* ¨ p) and 1La ¨ 1A (primary p*¨ p) transitions respectively. Emission spectra of the compound have shown fluorescence at 572, 442 and 345 nm.

 

Indian Journal of Pure & Applied Physics

Vol. 40, February 2002, pp. 95-106

Effect of basic temperature gradients on

Marangoni convection in ferromagnetic fluids

N Rudraiah, I S Shivakumara & C E Nanjundappa

The effect of different basic temperature gradients on the onset of Marangoni ferroconvection is studied. The resulting eigenvalue problem is solved by Galerkin technique for the lower boundary rigid and either conducting or adiabatic and the upper boundary at which the surface tension acts is free adiabatic. The results indicate that the stability of Marangoni ferroconvection is significantly affected by basic temperature gradients and the mechanism for suppressing or augmenting the same is discussed in detail. It is found that, the results obtained under the limiting conditions compare well with the existing ones.

 

Indian Journal of Pure & Applied Physics

Vol. 40, February 2002, pp. 107-110

Study of influence of pre-heat treatment on thermoluminescence glow curve pattern and related trapping parameters of technologically important synthetic quartz specimen

Y D Kale, Y H Gandhi & T R Joshi

 

The observed thermoluminescence(TL) glow curve patterns of laboratory grown synthetic quartz have been plotted as glow peak intensity ratio of low temperature glow peak to that of high temperature glow peak against either duration or temperature of pre-heat treatment. Systematic changes in this intensity ratio with the changes in pre-heat treatment conditions are observed. The systematic shifting of TL glow peak position towards lower temperature side with the changes in duration of pre-heat treatment has also been reported. The observed facts are explained on the premise of colour centres involved and phase transformation of quartz specimens when pre-heat treated at high temperature. The interpretations are well-supported by trapping level characterization also.

 

Indian Journal of Pure & Applied Physics

Vol. 40, February 2002, pp. 111-114

Application of light scattering for the determination of molecular parameters: Polystyrene balls

Ritesh Kumar Dubey, R K Pandey & D N Tripathi

 

Average molecular weight, radius of gyration and second virial coefficient have been determined for polystyrene balls using the static laser light scattering method. Reported results are quite reasonable and therefore, could be used to estimate other physical parameters for the sample.

 

Indian Journal of Pure & Applied Physics

Vol. 40, February 2002, pp. 115-121

Fluorescence studies of biphenyl doped by pyrene and perylene

S R Pujari, S A Jadhav, P N Bhosale, P M R Raoa & S R Patil

Fluorescent biphenyl absorbing short wave UV radiation and emitting at long wave UV radiation has been used as a solid matrix and its luminophors have been prepared by adding intentionally fluorescent pyrene and perylene impurities. From the fluorescence spectra it is seen that the pyrene impurity shifts the UV fluorescence of biphenyl towards red. Pyrene doped biphenyl emits in blue region at a wavelength of maximum emission 458 nm due to formation of exciplex. Incorporation of perylene into bicomponent biphenyl-pyrene system gave tricomponent crystal systems emitting in green region of visible spectrum. The fluorescence spectra of tricomponent biphenyl are broad structureless bands with maximum emission at 501 nm. These emission bands are interpreted as arising due to exciplex formation between pyrene and perylene in biphenyl matrix.

 

Indian Journal of Pure & Applied Physics

Vol. 40, February 2002, pp. 122-131

Structural and optical properties of monolithic silica-gel glasses containing Nd+3 using two different precursors TEOS and TMOS prepared by sol-gel technique

I K Battisha

 

The sol-gel process was applied for the preparation of neodymium (Nd3+) containing silica gel. Two different procedures have been studied using two different precursor materials (TMOS) and (TEOS), giving silica gel and silica containing Nd3+ of type I and type II, respectively. The absorption edge was determined. The normal transmission was measured using Fourier transform infrared spectrometer FTIR. Raman analysis and X-ray diffraction (XRD) were carried out to determine the crystal structure of the prepared samples. The thermally treated sample microstructures were investigated using scanning and transmission electron microscope. Microheterogeneities with amorphous nature are found at lower temperature, where crystalline phase appeared at higher temperature. Also DTA and TGA characteristic techniques were used. The photoluminescence PL measurements were carried out.

 

Indian Journal of Pure & Applied Physics

Vol. 40, February 2002, pp. 132-136

Development of fiber optic pH meter based on colorimetric principle

A L Chaudhari & A D Shaligram

A fiber optic pH sensor, having construction of probe based on the colorimetric principle is described. The probe consists of a bundle of fibers with the central fiber as receiving fiber and the outer ring of fibers as transmitting fibers. The LEDís of different colours are used as source and photodiode as detector. The probe is tested with pH buffer solution prepared by the usual method with universal indicator to get coloured solutions depending upon value of pH. The changes in the vicinity of the sensitive tip cause a variation in attenuation of specific reflected visible radiation bands. Initial results and performance specifications using externally added universal indicator are described.

 

Indian Journal of Pure & Applied Physics

Vol. 40, February 2002, pp. 137-140

Measurement of half-life of iridium-192 (HDR brachytherapy)by clinical dosimeters

Alok Kumar and Sudama Singh

Iridium-192 is a very common radioisotope, used in the treatment of the cancer patients worldwide. Usually the treatment is performed by brachytherapy, with remote afterloader machine of high dose rate (HDR). Half-life of iridium-192 varies from 73.83 to 74.2 days. In clinical practice, the calibration of iridium-192 is performed by clinical dosimeters. The authors used clinical dosimeters of 0.6 cc graphite thimble chamber with calibration jig and a re-entrant/well-type chamber to perform comprehensive measurements of half-life of iridium-192. There were six different iridium-192 radioisotopes taken one by one up to their clinical lifetime for measurement on routine basis. It was found that each individual iridium-192 source has a single decay constant and half-life ranging from 73.81 to 73.84 days with a mean value of 73.825 days. The standard deviation was found to be Ī 0.0084.

 

Indian Journal of Pure & Applied Physics

Vol. 40, February 2002, pp. 141-148

Study of electric field, Aitken nuclei, gaseous concentrations and

ionic conditions in contrasting environment

S S Kandalgaonkar, M I R Tinmaker, M K Kulkarni & Asha Nath

 

Ground based observations of electric field, Aitken nuclei (AN) and concentration of trace gases in fair weather conditions were made at four locations having different environmental status (oceanic, hill-top, semi-urban and industrial). The effect of concentrations of Aitken nuclei and trace gases on atmospheric electric field at these locations was examined and an attempt was made to obtain effective attachment coefficients and mean life time small ions at the locations. The results showed that in clean and relatively less polluted regions the diurnal as well as monthly mean variation of fair weather electric field was significantly (0.01%) correlated with Aitken nuclei concentration. An examination of gaseous concentrations suggested that the electric field was observed to be adversely affected in the regions which were enriched with the SO2 loading and the particulate matter from the industries. The values of attachment coefficients and mean life time of small ions obtained in the present set of study revealed that environmental status is an important factor to affect the air pollutants which in turn affect the electrical parameters.