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Vibrational study of crystal phase transitions in pyrrole (C 4 H 5 N) and C 4 D 5 N
Author(s) -
Lautie A.,
Romain F.
Publication year - 1990
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.1250210711
Subject(s) - raman spectroscopy , phase transition , pyrrole , phase (matter) , hydrogen bond , crystal (programming language) , atmospheric temperature range , infrared spectroscopy , chemistry , infrared , crystal structure , crystallography , amplitude , analytical chemistry (journal) , materials science , molecule , physics , condensed matter physics , thermodynamics , optics , chromatography , organic chemistry , computer science , programming language
Infrared and Raman spectra of crystalline pyrrole and pyrrole‐ d 5 were recorded in the range 5–4000 cm −1 . The behaviour of internal and external modes was studied as a function of temperature between 200 and 5 K. Two phase transitions were observed at 67 and 30 K and their mechanism is discussed. For the incommensurate phase, between 67 and 30 K, the amplitude and phase modes were identified at about 20 and 10 cm −1 , respectively; for the first, a critical exponent of 0.30 was determined. No evidence of NH … π hydrogen bond participation in the transitions has been detected.