Location of conical intersections in solution using a sequential quantum mechanics/molecular dynamics method

An extended version of the ASEP/MD method oriented to the study of the solvent effects on the structural and energetic properties of minimal energy crossing points between different potential energy surfaces is presented. The method, based on an extension of Bearpark’s proposal to the case of solvated molecules, permits to locate conical intersections and intersystem crossings both in equilibrium and non-equilibrium solvent conditions. As an application we studied the s-trans-acrolein 1(n → π∗) singlet–singlet conical intersection in aqueous solution. The ground and excited state surfaces of the solute molecule are described at CASSCF level while the solvent structure is obtained from molecular dynamics simulations.