Chemiluminescence in 5 µm multiple-photon decomposition of W(CO)6 in the presence of O2

Abstract

The infrared (at 5 µm) multiple-photon decomposition (IRMPD) of low-pressure W(CO)₆ in the presence of O₂ has been investigated using UV–VIS emission spectroscopy, where structureless broad chemiluminescence was observed over the time region of a few gas-kinetic collisions. The luminescence consisted of two broad bands which presumably belong to two different transient species, one being a ‘red’ band with a peak at 17 200 cm^–1(ca. 580 nm) of 7400 cm^–1 fwhm and the other a ‘blue’ band with a peak at 24 400 cm^–1(ca. 410 nm) of 13 700 cm^–1 fwhm. Kinetic studies suggest that both emitting species are produced through bimolecular reactions between O₂ and primary photofragments of IRMPD of W(CO)₆, tentatively assigned to highly coordinatively unsaturated tungsten carbonyl species, W(CO)_x(x⩽ 4).