RAMAN FREQUENCIES OF THE TA PHONON MODE OF $NH_{4}Cl$ CLOSE TO PHASE TRANSITIONS

Yurtseven, H.; Sherman, W. F.

RAMAN FREQUENCIES OF THE TA PHONON MODE OF $NH_{4}Cl$ CLOSE TO PHASE TRANSITIONS

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Date

1992

Authors

Yurtseven, H.

Sherman, W. F.

Publisher

Ohio State University

Abstract

The Raman spectra of $T A M$ ( $93 c m −1$ ) lattice mode of $N H 4 C l$ were obtained as functions of temperature in

Description

the tricritical (P $→ \leftarrow 1.6 k b a r 4$ ) and in the second order (P$\mathop{}^{\rightarrow}\kern -10 pt{_\leftarrow}$2.8 kbar) phase region. Our Raman data indicate a small discontinuity accompanied with continuity in the frequency shifts at $≃$ 1.6 kbar (tricritical). At $≃$ 2.8 kbar this discontinuity seems to disappear as the system changes its phase from a first order to a second order one. The Raman spectra of the $T A M$ ( $93 c m −1$ ) mode of $N H 4 C l$ are presented.

Author Institution: Department of Physics, Istanbul Technical University; Department of Physics, King's College London

URI

http://hdl.handle.net/1811/12636

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Abstracts of OSU International Symposium on Molecular Spectroscopy 1990-1999

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