The lineshape of motion-averaged isotropic Raman spectra

✍ Scribed by A.I. Burshtein; S.G. Fedorenko; A.Yu. Pusep

• Publisher: Elsevier Science
• Year: 1983
• Tongue: English
• Weight: 337 KB
• Volume: 100
• Category: Article
• ISSN: 0009-2614
• DOI: 10.1016/0009-2614(83)80704-0

✦ Synopsis

The conventional Kubo model can be used to describe the spectrum modulation by slow to fast motion, i.e. even in the range of applicability of perturbation theory. However, the Kubo model assumes the gaussian shape of static spectra. A model free of this assumption has been used to show that experbnental data can be interpreted provided the initial static spectrum has nongaussian wings. 1_ introduction 2. Nongaussian static spectra Adiabatic perturbations of vibrational levels affect essentially the shape of vibrational spectra. These perturbations, caused by interactions of the medium molecules, lead to a random modulation of the vibrational transition frequency 6+,ib = w. + Am(t), where o. is the average transition frequency, and Am(t) is the centred random process. Lately this phenomenon was termed vibrational dephasing [I]. It is often described in terms of the stochastic theory of lineshape (the Kubo model) [Z-S], while in the case of fast modulation the perturbation theory is used [9-13]_