AJP	ISSN : 0971 – 3093 Vol  5, No. 3, July-September, 1996

Asian
Journal of Physics

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Vol  5, No. 3, July-September, 1996

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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

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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.
References

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
2. Hirschfelder J O.J Chem Phys, 8(1940)431.
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, 2^nd Edn, (Addison-Wesley Publishing Co, Inc Cambridge, Mass (USA), page 50, (1978)
5. Shanker R , Ph D thesis, Banaras Hindu University, India, 1994.

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

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.

References

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 5^th 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

 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

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.

References

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

 Vol 5, No 3,(1996) 245-246

FTIR and laser Raman spectra of complex of Mn(II) with 2-thiouracil

J K Gupta, Sudhir Kumar, Satyendra Kumar and S D Kaushik*

Department of Physics

L R College (CCS University, Meerut),Sahibabad-201 005, India

Metal complexes of Mn(II) with 2-thiouracil of the composition [Mn(C₄H₄N₂OS)3H₂O] has been synthesized 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. © Anita Publications. All rights reserved.

References

1.       Rastogi V K, Mital H P,Sharma S N, Procd. XI International Conf on Raman Spectroscopy, (John Wiley & Sons, N Y), 1988,p 87.

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

3.       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.

4.       Rastogi V K, Mital H P, Arora C B, Gupta S L, Proc. 6^th European conf on the spectroscopy of biomolecules,(Kluwer Academic Publications: The Netherlands),1995.

Vol 5, No 3(1996) 247-248

FTIR and laser Raman spectra of 5-iodourail

Sudhir Kumar, S K Singhal¹, J P Goel² and M Srivastava³

Physics Department, L R College, Sahibabad-201 005, India

¹Department of Physics,Agrasain Degree College, Sikandarabad-203 205,India

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

FTIR (200-4600 cm^-1) and laser Raman(10-2000 cm^-1) spectra of 5-iodouracil have been recorded. The spectra have been analysed assuming C_s point group symmetry and the observed fundamentals have been assigned to different normal modes of vibration. ©Anita Publications All rights reserved.

References

1.       Sharma V, Sharma S D, Seema,Yada B S, Asian J Phys, 3(194)229.

2.       Bandekaar J, Zundel G, Spectrochim Acta, 39A(1983)343.

3.       Szezesniak M, Nowak M J, Rostkowska H, Szezesniak K, Person W B, Shugar D, J Am Chem Soc,105(1983)5969.

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

5.       Rastogi V K, Mital H P, Sharma Y C, Sharma S N, Spectroscopy of Biological Molecules, Eds R E Hester, R B Girling, (Royal Society of Chemistry),1991, p 403.

                                                                                       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

and

S D Pandey  

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

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 ⁸S_7/2 of Eu²⁺ ions to the splitted crystal field 5d orbitals. The high-energy band is due to transitions  from the ground statet of  the E_g component of the 4 f ⁶(5d) configuration, while the low energy band is attributed to the T_2g 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.