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Resonance Raman Scattering in Photodissociating Halomethanes
Author(s) -
Duschek F.,
Schmitt M.,
Vogt P.,
Materny A.,
Kiefer W.
Publication year - 1997
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(199706)28:6<445::aid-jrs126>3.0.co;2-4
Subject(s) - overtone , raman spectroscopy , chemistry , resonance (particle physics) , spectral line , raman scattering , laser , excitation , absorption (acoustics) , absorption spectroscopy , analytical chemistry (journal) , molecular physics , atomic physics , materials science , optics , physics , electrical engineering , chromatography , astronomy , composite material , engineering
Gas‐phase resonance Raman spectra of the halomethanes CH 3 I, CH 2 ICl and CH 2 I 2 were recorded with excitation wavelengths of an argon ion laser between 275.4 and 363.8 nm. The 275.4 nm laser line is resonant with the A‐band absorption transition of the molecules CH 3 I and CH 2 ICl and was used for Raman excitation. Resonance Raman spectra of these two molecules are then dominated by an overtone progression of the resonance enhanced C–I stretching mode and weak combination bands. The structure of the resonantly enhanced vibrational bands 3 1 –3 4 of CH 3 I are interpreted in terms of hot bands and rotational transitions in symmetric top molecules. The spectra of this mode (3 1 –3 4 ) were simulated applying a model for linear and for non‐linear symmetric top molecules. For CH 2 I 2 , which has four absorption maxima between 230 and 370 nm, further excitation wavelengths of an argon ion laser (335.1, 351.1 and 363.8 nm) were used to record resonance Raman spectra. All these spectra show several overtones and combination bands of the symmetric and antisymmetric CI 2 stretching modes ν 3 and ν 9 . © 1997 John Wiley & Sons, Ltd.