Simulation of ultrafast intersystem crossing using correlated single-reference methods

If you want to do surface hopping dynamics and you do not want to be excessive in your use of computational resources, you have two main options: CASSCF and TDDFT. In the case of CASSCF you have to be really careful when choosing your active space in order to get reasonable results. In the case of TDDFT you have to be really careful when choosing your functional in order to get reasonable results. That is why I am usually not too excited about either one of those methods. On the other hand, I am usually quite impressed by correlated single-reference methods such as CC2 and ADC(2), since they tend to provide good results at reasonable cost and do not require any additional input.

Some time ago we provided an implementation for using ADC(2) as available in Turbomole for surface hopping dynamics in Newton-X. This time, we went a step further and also included the possibility of computing intersystem crossings mediated by spin-orbit coupling using Turbomole with the help of Orca. This new functionality will be available within the next SHARC release (which is coming soon). The paper describing this work just appeared in JCP: "Surface hopping dynamics including intersystem crossing using the algebraic diagrammatic construction method."