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Vibrational study and molecular structure of two S 4 isomers in sulphur vapour
Author(s) -
Boumedien M. S.,
Corset J.,
Picquenard E.
Publication year - 1999
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/(sici)1097-4555(199906)30:6<463::aid-jrs397>3.0.co;2-d
Subject(s) - chemistry , raman spectroscopy , molecule , krypton , ion , wavelength , ring (chemistry) , infrared , analytical chemistry (journal) , argon , materials science , optics , organic chemistry , physics , optoelectronics
Raman spectra of sulphur vapour for two pressures (0.1 and 0.2 MPa) and various temperatures up to 700 °C were recorded using several krypton ion and argon ion laser exciting radiation wavelengths. Resonance Raman enhancement effects in conjunction with 32 S/ 34 S isotopic effects allow one to distinguish three fundamental vibrational modes (ν s , ν c , δ s ) of a green absorbing (λ max = 530 nm) chain‐like S 4 molecule from the modes belonging to S 3 and other cyclic S 6 , S 7 and S 8 molecules. Moreover, using a 647.1 nm excitation wavelength, several vibrational modes of another red absorbing (λ max = 560–660 nm) branched‐ring S 4 isomer were characterized. Finally, normal coordinate treatments confirm the trans planar C 2 h structure of the chain‐like S 4 species, whereas a comparison of the observed and calculated wavenumbers for the red absorbing S 4 isomer is in agreement with a branched‐ring structure. Copyright © 1999 John Wiley & Sons, Ltd.