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Low frequency Raman bands and space symmetries in sym‐tetrachlorobenzene
Author(s) -
Lin C. T.,
Pessine F. B. T.,
Srivastava R.,
Katiyar R. S.
Publication year - 1977
Publication title -
journal of raman spectroscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.748
H-Index - 110
eISSN - 1097-4555
pISSN - 0377-0486
DOI - 10.1002/jrs.1250060312
Subject(s) - raman spectroscopy , chemistry , homogeneous space , symmetry (geometry) , lattice (music) , phase transition , phase (matter) , lattice vibration , frequency shift , low frequency , molecular vibration , condensed matter physics , phonon , physics , optics , organic chemistry , geometry , mathematics , astronomy , acoustics
Abstract The external Raman active vibrational modes for sym‐tetrachlorobenzene single crystals have been recorded at different low temperatures. Accurate temperature dependent Raman measurements on frequencies and on relative intensities show that tetrachlorobenzene suffers a phase transition at T 0 = 160 ± 5 K. Group theoretical Correlation indicates that if the low temperature phase of tetrachlorobvenzene (α phase) is P1 symmetry, then one should observe nine lattice modes in the Raman spectrum; likewise, one should observe only six modes if the space symmetry of the β phase tetrachlorobenzene is P 1 . The fact that we do not see more than six external Raman peaks at lower temperatures suggests that the low temperature phase symmetry should be P 1 for tetrachlorobenzene.