An International Research Journal

AJP Vol 5 No 3, 1996


SSN : 0971 - 3093

Vol  5, No. 3, July-September, 1996

Vol 5, No 3, 1996

Asian Journal of Physics                                                                                                                     Vol 5, No 3(1996) 225-229

Direction-cosines for barrier height determination:A general formalism

R Shanker and  R A Yadav

Department of Physics

Banaras Hindu University, Varanasi-221 005, India


In determining barrier height of a top against free rotation, one requires the direction cosines of the top- axis relative to the principal axes. Determination of direction- cosines  for a top-axis in a non-planar molecule is not straight-forward. Therefore, a general formalism to determine direction- cosines of a top -axis has been presented for the first time.


1. Durig J R, Craven S M & Harris W C, Vibrational Spectra and Structure, Vol 1, Edited by J R Durig,(Marcel Dekker Inc,N Y),1972, p 73

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3. Colthap N B, Daly L H & Wiberley S E, Introduction to Infrared and Raman Spectroscopy,(Academic Press, N Y and London),1964.

4.Gerald C F, Applied Numerical Analysis, 2nd Edn, (Addison-Wesley Publishing Co, Inc Cambridge, Mass (USA), page 50, (1978)

5.Shanker R , Ph D thesis, Banaras Hindu University, India, 1994.

Direction-cosines for barrier height determination:A general formalism.pdf
R Shanker and R A Yadav


Asian Journal of Physics                                                                                                                       Vol 5, No 3(1996) 231-233

Laser Raman and IR spectra of complex of Co(II) with 2-thiouracil

Chander Bala Arora, Rachna Rastogi, Usha Awasthi* and Krishna

Department of Physics

Lajpat Rai College, Sahibabad-201 005, India

*Department of Zoology, Govt Girls College, Rewa, India


Stable complex of Co(II) with 2-thiouracil of the composition [Co(C4H4N2OS)3H2O] has been isolated in the solid state, and characterized on the basis of chemical analysis, magnetic measurement, IR and Raman spectral studies. The spectral studies indicate that the ligand 2-thiouracil acts as monodentate and coordination takes place through sulphur of (C2=S) group.

The ligand and its Co-complex were tested for their activity against Dalton’s lymphoma and it was found that they are effective antitumor agents.


1. Rastogi V K, Lal B, Sharma Y C & Jain C L, Metal ions in biology and medicine, (John Libbey, Eurotext, France), 1992, p 184

2. Rastogi V K, Singh Ajay, Chawla S C & Gupta S L, Procd 5th European Conf on the Spectroscopy of Biomolecules, (Kluwer Academic Publications, The

    Netherlands),1993,p 203.

3. Rastogi V K, Mital H P & Sharma S N, Indian J Phys B, 64 (1990) 312.

4. Rastogi V K, Lal B, Arora C B & Gupta S L, Procd. IXV International Conf on Raman Spectroscopy, (John Wiley & Sons, N Y)), 1994,p 952.

5. Sathyanarayana D N &  Kashmir Raja S V, Spectrochim Acta, A41(1985)809

6. Rastogi V K,  Singhal S K, Upadhyay M & Dublish A K, Procd.XV International Conf on Raman Spectroscopy, (John Wiley & Sons), 1996.


Asian Journal of Physics                                                                                                                         Vol 5, No 3(1996) 235

Thermodynamics of 4-amino-2-chlorobenzonitrile molecule

Sudhir Kumar1 D K Jain2, Sushma Arora1 and Y C Sharma3

1Department of Physics, Lajpat Rai College, Sahibabad-201 005, India

2Department of Physics, Meerut College, Meerut-250 001, Meerut

3Department of Physics, NAS College, Meerut, India


The present note reports the thermodynamical functions viz enthalpy, heat capacity, free energy and entropy of 4-amino-2-chlorobenzonitrile molecule, calculated using vibrational frequencies obtained from IR and Raman spectra of the molecule.


1. Sharma Y C, Yadav B S & Pandey A N, Asian J Phys, 3(1993)175.

2. Rastogi V K, Jain D K & Sharma Y C, Asian J Chem, 3(1991)113

3.Hellwege K H & Hellwege A M (Eds), Landolt Barnstein Numerical Data and Fundamental Relationships in Science and Technology New Series: Structural Data for Free Molecules, (Atomic and Molecular Physics), Vol 7, 1976 and Supplement to volume II/7, Vol 15, 1987. Springer Verlag, Berlin, 1976,1987.


Asian Journal of Physics                                                                                                          Vol. 5, No 3 (1996) 283 -289

Emission and Excitation Studies in Eu2+ and Mn2+ Doped KBr

A K Mishra

Physics Department, NAS College, Meerut- 250 004 , India


S D Pandey  

cPhysics Department, PPN College, Kanpur- 2008 001,  India


The optical emission and excitation spectral studies in KBr: Eu2+ and Mn2+ single crystals  at, different sample conditions have been analysed to identify the various aggregates and precipitates of both impurities and possible energy transfer from one impurity to another. The emission  obtained at 525 nm in the  both grown samples at  RT and LNT is proposed to be due to radiative energy transfer from Eu2+  to  Mn2+ ions, the latter being in Suzuki phase. The RT emission spectra of the samples annealed  for long time at 220 °C and LNT emission spectra of as grown samples identify the growth of different aggregates of Eu2+  and Mn2+ ions at the expense of (I-V) dipoles of the two impurities. © Anita Publications. All rights reserved.

Keywords: KBr, Suzuki phase, Eu2+ and Mn2+ single crystals

Total Refs: 31


1 Introduction

         Many investigations have been devoted to divalent impurity doped  alkali halide crystals which exhibt intetresting peculiarities due to the presence of a cation vacancy compensating the electrical extra charge of the divalent ion. The resulting (I-V) pairs have been studied by different techniques as optical [1-5], EPR [6], ITC and ionic conductivity studies [8].

            Particularly, the optical properties of Eu2+ ions in alkali halides are fairly well understood. The Eu2+ -ions doped in KBr host have two absorption bands [3] in the UV region of the spectrum, with peak positions at 250 nm and 344 nm. These bands are due to dipole allowed transitions from the ground state 8S7/2 of Eu2+ ions to the splitted crystal field 5d orbitals. The high-energy band is due to transitions  from the ground statet of  the Eg component of the 4 f 6(5d) configuration, while the low energy band is attributed to the T2g component of this configuration. As these transitions are dipole allowed, their oscillator strengths are high making the Eu2+ -doped KBr system an efficient absorber of UV light.

            The optical properties [9,10] of Mn2+ ions in alkali halides are also fairly well understood. The absorption bands of Mn2+ ions in alkali halides  are relatively weak because these arises from spin and parity forbidden transitions. The oscillator strength of these transitions is around 10–7, which  makes Mn2+  doped systems weak absorbers of UV light. 


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