Table of Contents
Laser Chemistry
Volume 16, Issue 4, Pages 255-264
http://dx.doi.org/10.1155/1996/34032

Selective IR Laser Induced Isomerization and Dissociation of BIS (Trifluoromethyl) Ketene Molecules

Institute of Spectroscopy, Russian Acad. Sci., 142092 Troitzk, Moscow Reg., Russia

Received 21 December 1995

Copyright © 1996 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Multiphoton IR laser induced isomerization and dissociation of (CF3)2C=C=O (FMK) molecules have been studied. The antisymmetric stretch v1 = 2192 cm-1 of C=C=O—and antisymmetric v16 = 991 cm-1 of C—C— bonds were excited by the second- and first harmonics of a pulsed TEA CO2 laser. The dependence of isomerization conversion on laser radiation frequency, fluence, and number of shots was measured. The isomerization channel was predominant compared with dissociation for the conditions of IR multiphoton excitation under study.

The isomerization of FMK by the second–harmonic radiation of a CO2 laser was proved to be selective with respect to oxygen isotopes. The isomerization product (FMA molecules) was enriched with 18O with maximum value of selectivity α(18/16) = 3.9 when FMK molecules were excited at 2ωlas = 2143.8 cm-1.