Absolute and relative rate coefficients in the IR-laser chemistry of bichromophoric fluorobutanes: tests for inter- and intra-molecular selectivity

Abstract

Hydrogen fluoride elimination after IR-multiphotoh excitation with pulsed CO 2 laser radiation has been studied quantitatively with fluences up to 20 J cm −2 for FCH 2CH 2CH 2CH 3, FCH 2CH 2CH 2CH 2F, FCDHCH 2CH 2CH 3, and FCDHCH 2CH 2CH 2F. Efficient isotope separation shows that the R-CHDF chromophore can be selected near 930 cm −1, in agreement with spectroscopic evidence. The absence of mode- or site-selective reaction in FCDHCH 2CH 2CH 2F at inert gas pressures up to 10 5 Pa leads to a rough estimate for an intramolecular energy redistribution rate coefficient k intra > 10 10-10 11 s −1.