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Etude par Spectrométrie Raman de la Transition de Phase Structurale des Tétrachloro et Tétrabromo‐1,2,4,5 Benzenes
Author(s) -
Pasquier B.,
Le Calvé N.
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.1250060311
Subject(s) - raman spectroscopy , chemistry , phase transition , crystallography , exponent , physics , condensed matter physics , optics , linguistics , philosophy
Raman and infrared spectra of crystalline1,2,3,4,5‐tetrachloro‐ and tetrabromobenzenes have been analysed between 10 and 100 cm −1 over a range of temperature from 10 K to 400 K. An assignment of lattice modes is given. The first‐order phase transition is of a displacive type as shown by the behaviour of librational modes. The small value of the estimated β critical exponent in the ν T /ν 0 = (T c − T/T c )β experession is interperted in terms of predominant short‐range interactions in these molecular crystals.