Quantum Dynamics in an Explicit Solvent Environment: A Photochemical Bond Cleavage Treated with a Combined QD/MD Approach.

In quantum chemistry methods to describe environmental effects on different levels of complexity are available in the common program packages. Electrostatic effects of a solvent for example can be included in an implicit or explicit way. For chemical reactions with large structural changes additional mechanical effects come into play. Their treatment within a quantum dynamical context is a major challenge, especially when excited states are involved. Recently, we introduced a method that realizes an implicit description. Here, we present an approach combining quantum dynamics and molecular dynamics. It explicitly incorporates the solvent environment, whereby the electrostatic as well as the dynamic effects are captured. This new method is demonstrated for the ultrafast photoinduced bond cleavage of diphenylmethylphosphonium ions (Ph2CH-PPh3(+)), a common precursor to generate reactive carbocations in solution.