PNNL

Abstract

We have studied the effects of UV radiation on HBr-acetone Ar Matrices. Results indicate photoproducts formed from the irradiation of these matrices depend on the wavelength of light used. Irradiation at 266 and 309 nm results only in the loss of the H-bonded HBr-acetone complex and the photo-production of an HBr-1-propen-2-ol complex. Ab initio calculations of HBr-1-propen-2-ol complexes support this finding. Irradiation at 193 nm shows a high degree of fragmentation of all molecules as indicated by CH4, CO, and CO2 product peaks in the infrared spectrum and the loss of all peaks associated with HBr, acetone and their complex. In contrast, irradiation at 355 nm shows no change in the infrared spectra even after prolonged irradiation. For 266 and 309 nm light, a minor photoreaction channel to a non-H-bonded HBr-acetone complex is also noted.