Activation of acetonitrile by gas-phase uranium: bond structure analysis and spin-flip reaction mechanism.

The reaction mechanism of uranium atom with acetonitrile molecule has been systematically studied on the quintet and triplet spin-state potential energy surfaces (PESs) at B3LYP level of density functional theory. Reaction site prediction and bonding evolution were analyzed using different methods. Crossing seams and possible spin inversion processes between different PESs are discussed by means of spin-orbit coupling (SOC) calculations. The results show that there are three crossing points in the reaction, which appear in the process of capturing hydrogen atom. Larger SOC constant (1545.80 cm) and intersystem crossing (ISC) probability (< P > = 0.72) between quintet and triplet indicate that the effective ISC would occur in the vicinity of the minimum energy crossing points. [ABSTRACT FROM AUTHOR]