PNNL

Abstract

Laser-ablated U and Th atoms react with CO2 to give OUCO (1806.9, 823.2 cm-1) and OThCO (1778.4 cm-1) as major products, which are identified by isotopic substitution (13CO2, C18O2 and 12CO2 + 13CO2, C16O18O + C18O2 mixtures), doping with CCl4 as an electron trap, and comparison with frequencies from density functional calculations. The insertion reaction is spontaneous as these bands increase on annealing the neon matrix from 4 to 6 K. Further reaction of OAnCO (An ) Th, U) with another CO2 molecule gives the O2An(CO)2 product, although much more so with uranium than thorium. Reaction of the metal cations with CO2 produces OUCO+ (2073.0, 881.2 cm-1) and OThCO+ (2009.9, 896.4 cm-1) with higher yield in thorium experiments. The O2An(CO)2 - anions are observed for both metals again with higher yield in uranium investigations.