Isotopic selectivity in the laser induced dissociation of molecules with overlapping absorption bands

Abstract

Measurement of the isotopic selectivity as a function of temperature are described for IR laser induced dissociation of UO2(hfacac)2⋅THF in a low density molecular beam. The measured selectivity was found to increase from 1.2 at 120 °C to 1.9 at 65 °C. This behavior is consistent with a model which takes into account both the initial thermal energy content of the molecule and the energy barrier to dissociation. Indeed, such behavior is expected for any complex molecule which has isotopically shifted, but overlapping absorption spectra as is the case for the 235U and 238U containing molecules used in this study.