Temperature-dependence study of infrared- and raman-band shapes of the 834(A1) transition in thiophene

✍ Scribed by J.P. Pinan-Lucarre; L. Colombo; J. Loisel; M. Le Postollec; T. Nguyen Tan

• Publisher: Elsevier Science
• Year: 1977
• Weight: 539 KB
• Volume: 10
• Category: Article
• ISSN: 0378-4487
• DOI: 10.1016/0378-4487(77)80010-1

✦ Synopsis

Widths and shapes of v3(Al) infrared and Raman bands of thiophene at a34 cm-1 have been studied in the liquid and plastic phases. Since the depolarisation ratio of the band is very small at room temperature, the results obtained by the two techniques applied allow accurate determination of vibrational and rotational correlation functions and correlation times for different temperatures. frequency spectroscopy, middle infrared, and Raman spectroscopy, are often required. The low-frequency spectrum (microwave and far infrared) provides only the vectorial orientational correlation function [6]. The function thus obtained is not a monomolecular one, as it is in the IR or Raman spectrum. Raman spectroscopy alone can, at best , give only vibrational and tensorial rotational correlation functions. On the other hand, comparison of IR and polarised Raman measurements provides the possibility of determining vibrational and rotational (vectorial and tensorial) correlation functions separately [6]. In the present work we have made such a comparison at different temperatures in order to study, in detail, correlation functions for a totally synrmetric vibrational transition of the thiophene molecule. INFRARED AND RAMAN BANDSHAPES. (THEORY AND O~~BJARISON).

In this section we briefly review the results of Raman and IR bandshape theories developed by several authors [2-51. Initially, these theories were applied to diatomic molecules in an inert solvent; recently, however, these considerations have also been extended to polyatomic molecules.