Indian Journal of Pure and Applied Physics
___________________________________________________________________________________
VOLUME 39
NUMBER 11
NOVEMBER 2001
__________________________________________________________________________________________
CONTENTS
Nuclear Physics
Irradiation of thymine by O16 heavy ion in aerated condition
Pratyush Purkayastha*, A N Talukdar & A Sarma
691
Atomic and Molecular Physics
Studies on fluid structure and molecular interactions of amines
T Thenappan* & M Subramanian
694
Physics of Gases, Plasmas and Electric Discharge
Analysis of nitrogen ion beam produced in dense plasma focus device using Faraday Cup
H Bhuyan, S R Mohanty* & T K Borthakur
Condensed Matter: Structure, Mechanical and Thermal Properties
Effect of In content in Inx Ga1-x Sb on breaking of ampoule during growth by
vertical directional solidification
P Shashidharan*, N A Gokhale, D B Gadkari, K B Lal, M R Gokhale & B M Arora
Condensed Matter: Electronic Structure, Electrical, Magnetic and Optical Properties
Microwave absorption and relaxation processes of ternary mixtures of non-rigid polar liquids
G D Rewar & D Bhatnagar*
Modelling of X-ray K-absorption parameters of cobalt (II) complexes with Wiener indices
Ashutosh Mishra*, Maneesh Dave, P V Khadilkar, Dilip Pandey & Pooja Sharma
Impedance spectroscopic studies in SrBi4Ti4O15
N Venkat Ramulu, M Aparna, G Prasad, G S Kumar* & T Bhima Sankaram
Polyaniline thin film-porous silicon sensors for detection of microorganisms
S C K Misra* & R Angelucci
Analytical model for saturation drain current and substrate current of fully overlapped LDD MOSFET
Anil Kumar, Ekta Kalra, Srikanta Bose, Adarsh Singh, Simrata Bindra, Subhasis Haldar &
R S Gupta*
Microwave and laser Raman spectroscopy of o-chlorotoluene
K P R Nair* & Shibu M Eappen
Optical study of some nematic mixtures
P P Anand, Rajbir Singh, V K Agarwal* & B Bahadur
Interdisciplinary Physics and Related Areas of Science and Technology
Studies on indoor radon/thoron and their progeny levels at Mysore city, Karnataka state
L A Sathish, J Sannappa, L Paramesh*, M S Chandrashekara & P Ventaramaiah
Radon monitoring in underground water of Gurdaspur and Bathinda districts of Punjab, India
H S Virk*, V Walia & B S Bajwa
____________
*The corresponding author has been indicated by (*) mark in case of papers with more than one author
698
704
707
714
718
726
731
750
752
738
746
Indian Journal of Pure & Applied Physics
Vol. 39, November 2001, pp. 691-693
Irradiation of thymine by O16 heavy ion in aerated condition
Pratyush Purkayastha1, A N Talukdar1 & A Sarma2
1Department
of Physics, Gauhati University, Guwahati, Assam 781 014
2Nuclear
Science Centre, New Delhi 110 067
Received 28 March 2001, accepted 4 September 2001
Aqueous solutions of thymine have been irradiated with O16 heavy ion beam in aerated condition with different
concentrations. The degradation of thymine bases is monitored by the change in concentration with UV visible
spectrophotometer. The observed results have been compared with those reported earlier. The dose rate was found to be
decisive factor in determining the course of radiolysis.
Indian Journal of Pure & Applied Physics
Vol. 39, November 2001, pp. 694-697
Studies on fluid structure and molecular interactions of amines
T Thenappan & *M Subramanian
Department of Physics, Alagappa University, Karaikudi 630 003
Received 4 April 2001; revised 8 August 2001; accepted 24 September 2001
Fluid structure in amines could be readily studied by dielectric measurements by virtue of the influence of
local order and the overall dipole moment. The short range interaction between permanent dipoles could be
described by the Kirkwood-Frohlich correlation factor. In dilute solutions of amines with inert solvents, the
interaction between the solute species among themselves may be given by a modified form of the correlation
factor (g') by taking the solute-solvent and solvent-solvent interaction. Dielectric constant of the binary
mixtures of monoethanolamine and diethanolamine in 1,4 dioxan and triethylenetetramine and
cyclohexylamine in benzene were measured at 298, 308 and 318 K. The values of Kirkwood-Frohlich
correlation factor (g') were determined at the temperatures mentioned above. The results are interpreted in the
light of the theory. The presence of α and β multimers in the above systems was identified.
Indian Journal of Pure & Applied Physics
Vol. 39, November 2001, pp. 698-703
Analysis of nitrogen ion beam produced in
dense plasma focus device using Faraday Cup
H Bhuyan, S R Mohanty* & T K Borthakur
Centre of Plasma Physics, Dispur, Guwahati 781 006
and
R S Rawat
Department of Physics/ Electronics, SGTB Khalsa College, University of Delhi, Delhi 110 007
Received 23 December 2000; accepted 7 April 2001
A nanosecond response Faraday Cup was fabricated and employed to characterize pulsed ion beam of a 2.2 kJ Mather
type Dense Plasma Focus Device. The Faraday Cup operating in bias ion collector mode was used to determine the energy
spectrum and flux of fast nitrogen ion beam along the electrode axis (0) of the device. It has been possible to register the
ion energy up to a lower kinetic energy threshold of ~7 keV which is a value much lower than that obtained in any previous
works. The correlation of the ion beam intensity with filling gas pressure is also reported.
Indian Journal of Pure & Applied Physics
Vol. 39, November 2001, pp. 704-706
Effect of In content in InxGa1-xSb on breaking of ampoule during
growth by vertical directional solidification
P Shashidharan1, N A Gokhale3, D B Gadkari2, K B Lal3, M R Gokhale4 & B M Arora4
1Department
of Physics, Vartak College, Vasai Road (W), Mumbai 401 202
2
Department of Physics, Mithibai College, Vile Parle, Mumbai 400 056
3Department
4Solid
of Physics, University of Mumbai, Vidyanagari, Mumbai 400 098
State Electronics, Tata Institute of Fundamental Research, Mumbai 400 005
Received 28 March 2001; revised 27 June 2001
InGaSb crystals have been grown using vertical directional solidification (VDS) technique in closed conical quartz
ampoules. InxGa1-xSb Crystals with different In mole fractions in the melt (x = 0.1, 0.25, 0.5 and 0.75) have been grown to
study the effect of mole fraction on the breaking of the ampoule. Growth with In mole fraction x = 0.5 in the melt resulted
in breaking of the ampoule. For other compositions, no breaking of the ampoule occurred. The problem of breaking of
ampoule was circumvented by encapsulating the material containing quartz ampoule in another quartz ampoule. The double
ampoule prevents the melt from coming into contact with atmospheric air in case of a breakage enabling the growth of
crystals from melts with 50 % In composition. Sticking of the ingot to the ampoule has not been observed for any of the
compositions.
Indian Journal of Pure & Applied Physics
Vol. 39, November 2001, pp. 707-713
Microwave absorption and relaxation processes of
ternary mixtures of non-rigid polar liquids
G D Rewar & D Bhatnagar
Microwave Laboratory, Department of Physics University of Rajasthan, Jaipur 302 004
Received 2 March 2001; revised 24 July 2001; accepted 7 September 2001
The dielectric absorption of three acrylates and their mixture compositions as liquid dielectric samples have been
studied at MW frequency 9.132 GHz in dilute solution of carbon tetrachloride in the temperature range 300-330 K.
Different dielectric parameters like dielectric constant  and dielectric loss  at microwave frequency, dielectric constant
s at static frequency and dielectric constant  at optical frequency have been determined. Using these dielectric data,
distribution parameter , various relaxation times, viz. o, 1, and 2 of individual components and their ternary mixture
compositions have been calculated. Thermo dynamical parameters like molar energy of activation F molar enthalpy of
activation H and molar entropy of activation S have been evaluated by considering the relaxation as the rate process.
Variation of ln (2T) versus 1/T indicates exponential decay of relaxation time with temperature for dielectric relaxation
process. The relaxation time values for single component solutions agree well with literature values while relaxation times
of ternary mixture compositions are consistent with the computed values obtained from various theoretical relations.
Indian Journal of Pure & Applied Physics
Vol. 39, November 2001, pp. 714-717
Modeling of X-ray K-absorption parameters of cobalt (II) complexes
with Wiener indices
Ashutosh Mishra, Maneesh Dave, PV Khadikar, Dilip Pandey & Pooja Sharma
School of Physics, Devi Ahilya University, Indore 452 017
Received 5 October 2000, revised 13 July 2001, accepted 21 September 2001
An application has been used in modeling the X-ray absorption parameters. The use of Wiener index (W) for
estimating, predicting and comparing the X-ray K-absorption parameters of some cobalt (II) complexes of a series of
benzohydroxamic acid ligands has been described. The K-absorption parameters used are chemical shift (EK), fractional
oxidation number (Zeff), shift of principal absorption maximum and edge-width for this purpose. The results obtained with
regression analysis of the data show that Wiener indices (W) can be successfully used for estimating these parameters.
Indian Journal of Pure & Applied Physics
Vol. 39, November 2001, pp. 718-725
Impedance spectroscopic studies in SrBi4Ti4O15
N Venkat Ramulu, M Aparna, G Prasad, G S Kumar & T Bhima Sankaram
Materials Research Laboratory, Department of Physics, Osmania University, Hyderabad 500 007
Received 20 March 2001; revised 15 June 2001; accepted 22 August 2001
The impedance measurements have been performed in the temperature range of 30 to 600 C and the frequency range
1 kHz to 10 MHz on four-layered SrBi4Ti4O15. The imaginary components of impedance Z '', the electrical modulus M'' and
ac conductivity have been computed, both as a function of frequency and temperature. The peaks appear in Z'' versus
frequency plots and they shift towards lower frequencies at the temperature up to 500 C and above 525 C they shift
towards higher frequencies. Similar behaviour is observed in M '' versus frequency plots. |Z ''| values decrease with increase
of temperature, while |M''| values decrease up to 500 C and above 525 C these values are found to increase with
temperature. Complex impedance diagrams are nearly semicircles at higher temperatures. Results are interpreted in terms of
possible conductivity mechanisms present in the sample.
Indian Journal of Pure & Applied Physics
Vol. 39, November 2001, pp. 726-730
Polyaniline thin film-porous silicon sensors for detection of
microorganisms
S C K Misra & R Angelucci*
National Physical Laboratory, New Delhi 110 012
*CNR-LAMEL, Institute, Bologna, Italy
Received 15 May 2001, revised 2 August 2001, accepted 24 September 2001
Quick and simple methods to detect the type of life threatening microbial species are very essential in food and water
contaminated with bacteria. Recently, by utilizing the semiconducting polymeric thin films prepared on silicon
macroporous substrates a new technology for detection of micro-organisms has been developed. The advantages of the
polymeric devices are the ease of fabrication, the high sensitivity to micro-organisms, the fast response time and the room
temperature operation. In this work the current voltage characteristics and the dielectric losses variations of the specifically
doped polymeric thin films deposited on silicon macroporous membranes upon exposure to E. Colii were studied. The
sensors were prepared by vacuum depositing doped polyaniline in the form of thin films on the silicon macroporous
structures. The particular doping combination in the polymer makes the sensor specific for detection of E. Colii. Moreover
the sensitivity of the to E. Colii is very high and the response time of the sensor is about 5 sec. The total response time is a
few tens of seconds. The macroporous silicon substrate allows to obtain a polyaniline thin film with high specific surface
area and good crystallinity, as shown by SEM and X-ray investigations, respectively. Both the high surface area and the
crystallinity of the polyaniline film deposited on the macroporous silicon substrate are believed to be responsible for the
excellent properties of the sensor device. The fabrication process, the morphological, structural and electrical
characterization of the hybrid polymeric/ silicon micro-sensors in regard to detection of E. Colii have been described.
Indian Journal of Pure & Applied Physics
Vol. 39, November 2001, pp. 731-737
Analytical model for saturation drain current and substrate current
of fully overlapped LDD MOSFET
Anil Kumar, *Ekta Kalra, Srikanta Bose, Adarsh Singh, Simrata Bindra, **Subhasis Haldar & R S Gupta
Semiconductor Devices Research Laboratory, Department of Electronic Science,
South Campus, University of Delhi, New Delhi 110 021
Multi Media University, Jalan Ayer Keroh Lama, 75450, Melaka, Malaysia
Department of Physics, Motilal Nehru College, Benito Juarez Road, New Delhi110 021
Received 20 April 2001; revised 9 July 2001; accepted 27 July 2001
An analytic model for saturation drain current and substrate current of fully overlapped lightly doped drain
(FOLD) MOSFET is developed using pseudo-two-dimensional approximation in the channel and drain regions
and expression of maximum electric field is obtained. An expression for channel length modulation factor is
also developed and the substrate current is calculated.
Indian Journal of Pure & Applied Physics
Vol. 39, November 2001, pp. 750-751
NOTE
Microwave and laser Raman spectroscopy of o-chlorotoluene
K P R Nair & Shibu M Eappen
Laser and Spectroscopy Laboratory, Department of Physics,
Cochin University of Science & Technology, Cochin 682 022
Received 11 April 2001; accepted 7 September 2001
The microwave spectrum of o-chlorotoluene C6H4CH3Cl shows distinct rotational structures due to four excited
vibrational states over and above the ground state spectrum. The vibrational frequency calculated from the relative
intensities of the ground and first excited states in the microwave spectra is identified in the laser Raman spectra and is
believed to be the first torsional state of the molecule.
Indian Journal of Pure & Applied Physics
Vol. 39, November 2001, pp. 752-754
NOTE
Optical study of some nematic mixtures
P P Anand1, Rajbir Singh1, V K Agarwal2 &
B Bahadur3
1Physics Department, Meerut College, Meerut (UP)
2Physics Department, CCS University, Meerut (UP)
3Rockwell Collins Inc, Cedar Rapids, IA 52498-3161
Received 15 April, 2001; accepted 3 August 2001
Optical birefrigence study of four multi-component nematic mixtures E-80, E-90, E-100 and E-110 (all from E.Merck),
were carried out, providing information about their transition temperatures and microscopic order parameter (S).
Indian Journal of Pure & Applied Physics
Vol. 39, November 2001, pp. 738-745
Studies on indoor radon/thoron and their progeny levels
at Mysore city, Karnataka state
L A Sathish, J Sannappa, L Paramesh, M S Chandrashekara & P Venkataramaiah
Department of Studies in Physics, University of Mysore, Manasagangotri, Mysore 570 006
Received 17 April 2001; revised 2 July 2001; accepted 20 September 2001
Radon, thoron and their progeny concentrations have been measured in different types of buildings at different
locations in Mysore city over a period of 2 years using solid state nuclear track detector (SSNTD) method. The dose to the
selected population of Mysore city has been estimated. The arithmetic mean (AM) values of concentrations of radon and
thoron in indoor atmosphere ranged from 9.20 to 58.02 Bq m-3 with a median of 34 Bq m-3 and 7.21 to 59.27 Bq m-3 with a
median of 33 Bq m-3, respectively. The arithmetic mean of progeny concentrations varies from 0.033 to 2.52 mWL with a
median of 1.29 and 0.074 to 47.04 mWL with a median of 20.7, respectively. The dose to the selected population of Mysore
city has been found to be 1.58 mSv y-1. The concentrations of radon/thoron and their progeny vary with the type of flooring
and ventilation conditions. Diurnal and seasonal variations have also been observed. Higher radon concentration has been
found during nights and early morning hours.
Indian Journal of Pure & Applied Physics
Vol. 39, November 2001, pp. 746-749
Radon monitoring in underground water of Gurdaspur and Bathinda
districts of Punjab, India
H S Virk, V Walia & B S Bajwa
Department of Physics, Guru Nanak Dev University, Amritsar 143 005
Received 9 May 2001; revised 30 August 2001; accepted 11 September 2001
Radon monitoring has become a global phenomenon due to its health hazard. More than 55 % radiation dose delivered
to the human kind on the globe from all natural sources is due to radon alone. Radon measurements have been carried out in
groundwater in Gurdaspur and Bathinda districts of Punjab, India. Radon concentration values in potable water show a
wide variation depending on its source and location. Generally, radon concentration values in hand-pump drawn
groundwater have been found to be higher than the values determined for water supplied from other sources. Mineral water
has the minimum radon concentration compared with groundwater sources. No correlation is found between radon
concentration and uranium content of groundwater in Bathinda district.