Photochemically Induced Energy Transfer II: Spectroscopic and Photophysical Aspects of the Electronic-to-Electronic Energy Transfer in Geminate van der Waals Complexes

Abstract

A detailed spectroscopic study of the photochemically induced electronic-to-electronic energy transfer reported by us earlier (Gudipati, M. S. J. Phys. Chem. A 1997, 101, 2003) in O···CO geminate van der Waals complexes in Ar matrices revealed that these complexes are stabilized in two distinct sites, a singly substitutional (SS) site and a doubly substitutional (DS) site. In the SS site the spectra of O and CO are strongly perturbed, whereas in the DS site spectroscopic features nearly identical to the isolated O and CO have been observed. Theoretical calculations on the ground-state O···CO complex in the SS and DS sites of the Ar lattice are in agreement with the experimental observations. Photolysis of CO2 in Xe/CO2/Ar matrices leads to the formation of Xe···O···CO complexes, and energy transfer from the excited CO to XeO that results in emission from XeO has been observed. Electronic spectra corresponding to the O···CO complexes in Kr matrices have also been observed, but only as weak features superpo...