  For future use in modeling photoexcited dynamics and intersystem crossing, we
calculate spin-adiabatic states and their analytical nuclear gradients within
CIS the- ory. These energies and forces should be immediately useful for
surface hopping dynamics, which are natural within an adiabatic framework. The
resulting code has been implemented within the Q-Chem software and preliminary
results suggest that the additional cost of including SOC within the
singles-singles block is not large.
