An International Peer Reviewed Research Journal

Vol 9 No 1, 2000


SSN : 0971 - 3093

Vol  9, No. 1, January-March, 2000

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Asian Journal of Physics

Vol 9, No 1, (2000)



Simple variational principle I : Theory and application to thermoelectric phenomena

Christopher G Jesudason                                                                                                                                                                                          1


Photothermal spectroscopy and its application in characterisation of polycyclic aromatic hydrocarbons

R K Garg and Pardeep Kumar                                                                                                                                                                                  15


Techniques and applications of electron paramagnetic resonance spectroscopy                                                                

S K Gupta                                                                                                                                                                                                                  31


Force field for planar modes of fluorobenzene revisited                                                                                                           

J S Singh, D N Singh and R A Yadav                                                                                                                                                                         45


Spectroscopic studies of iron doped B203-Bi203 glasses                                                                                                              

L Baia, D Maniu, T Iliescu,S Simon, S Schlücker and W Kiefer                                                                                                                               51


I-V and C-V measurements on Al203 based MOS structures.                                                                                                                                  59

A C Sarmah and K C Barua


Mechano and electroluminescence spectroscopy of Cu and Mn doped ZnS phosphors                                     

R S Gupta, S P.Tamrakar, S K Sharma and B P Chandra                                                                                                                                         67


An approach for efficiency determination of HPGe detectors used in γ-ray spectroscopy techniques             

N Walley El-Dine                                                                                                                                                                                                       71


Structural studies of some polar molecular systems using microwave absorption technique and nuclear magnetic resonance  

S K Vaish and N K Mehrotra                                                                                                                                                                                     79


Lattice dynamics of tellurium subchloride- A Raman study     

Y S Raptis, E Anastassakis and A Topalidou                                                                                                                                                             85


Ionic character and dipole moments of alkali halides from their electronegativity data                                                    

K P R Nair and Usha John                                                                                                                                                                                         93


Correlative study of interplanetary plasma parameters during the period of 1978-83                                                       

V K Mishra, D P Tiwari and Pankaj K Shrivastava                                                                                                                                                   97


An evaluation of temperature dependent electrical resistivity ρ(T) and thermoelectric power S(T) for TiS2, Cox,TiS2 and NixTiS2             

M P Jha, A Singh and L K Mishra.                                                                                                                                                                             103


Optical limiting and nonlinear absorption studies in Bi12SiO20 crystal at high power nanosecond laser regime

P Sreeramana Aithal, R P Singh, P Prem Kiran and D Narayana Rao                                                                                                                     107


Structural and dielectric properties of Sr5RTi3Nb7O30 [R = Nd, Eu, Gd and Dy] ceramics

A Panigrahi, R N P Choudhary and B N Das                                                                                                                                                            115


Quantum mechanical study of CP violation                                                                                                                               

Vinita Sahoo and K P Sahu                                                                                                                                                                                        119


Conversion electron lines of a new gamma transition of 1.51 MeV in the decay of 207Bi                                                

R K Mishra, A Kumar, Shashi Prabha and S P Tiwari                                                                                                                                              121


Growth features and dislocation etching of In Bi0.8Se0.2                                                                                                            

G R Pandya, K R Shah and S M Vyas                                                                                                                                                                        124


 Asian Journal of Physics                                                                                                          Vol. 9, No 1 (2000) 45-50


Force field for planar modes of flurobenzene revisited

J S Singh,D N Singh and R A Yadav*

Department of Physics, Laser and Spectroscopy Lab, Banaras Hindu University, Varanasi-221 005, (India)


The force field calculations for planar modes of flurobenzene have been revisited using more accurately observed values of fundamentals [J Mol Spectrosc, 73 (1978)290] of parent molecule and its two deuterated analogues namely, flurobenzene –p-d and –d5. A 38 parameters force field has been determined leading to alteration of the earlier vibrational assignments for some of the normal modes. The doblet observed at 2274.4 and 2304.4cm-1 as A type IR bands for p-d fluorobenzene could be explained as arising due to the Fermi resonance between the (C-D) fundamental and the first overtone of the CHplanar bending mode observed at 1156 cm-1. Three force constants for the stretching of the c-c bonds of the ring have been taken in view of the C2v symmetry and similarly, 3 force constants for the CH stetchings and the bendings and 4 force constants for the planar ring bendings have been taken . It is found that the force constants involving different C-C bond stetchings vary within 2%, those involving CH strechings and bendings vary within 1% and 7.5% respectively . However, the force constants involving the ring bendings show rather a large variation of 28%.

Total Refs : 10

Force field for planar modes of flurobenzene revisited.pdf
J S Singh,D N Singh and R A Yadav


Asian Journal of Physics                                                                                                                 Vol 9, No 1 (2000) 51-57

Spectroscopic studies of iron doped B203-Bi203 glasses


Babes—Bolyai University, Physics Department, 3400, Cluj—Napoca, Romania

Institut fur Physikalische Chemie, Universitat Wurzburg, Am Hubland, D-97074 Wiirzburg, Germany


Raman and IR spectra of 99.5%[xB203(1—x)Bi203]0.5%Fe203 glasses with different Bi/B nominal ratios (0.20 ≤ x ≤ 0.80) have been investigated. The influence of bismuth atoms on the vitreous B203 network as well as the local order changes both around bismuth and boron atoms are studied. The very low content of Fe203 introduced in these samples has no structural effect on the bismuth-borate glass matrices as far as evidenced by the methods used.

Total Refs : 27

Spectroscopic studies of iron doped B203-Bi203 glasses.pdf


Asian Journal of Physics                                                                                                          Vol. 9, No 1 (2000) 107-114

Optical limiting and nonlinear absorption studies in Bi12SiO20 crystal at high power nanosecond laser regime

P Sreeramana Aithal, R P Singh, P Prem Kiran and D Narayana Rao


Nonlinear absorption properties of Bi12SiO20 (BSO ) crystal are studied using single beam Z-scan technique in the nanosecond regime without applying external electric field. We observed a strong nonlinear absorption at 532 nm (SHG of an Nd: YAG laser) and at 595nm (Nd:YAG pumped dye laser) . We have also studied the optical limiting and the laser damage threshold of the crystal at both the wavelengths.  A physical model is developed to explain the observed behavior using photorefractive properties of BSO crystal which incorporates the accumulative trap assisted excited state absorption and the instantaneous two-photon absorption which makes it as an excellent optical limiter.

References: 15



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