Direct diabatization of electronic states by the fourfold-way: Including dynamical correlation by multi-configuration quasidegenerate perturbation theory with complete active space self-consistent-field diabatic molecular orbitals

- Simplification of fourfold-way diabatization procedure.
- Improved algorithm for diabatic states for simulating photochemical dynamics.
- Complete active space SCF diabatic MOs for excited states with inclusion of dynamical correlation.