An alternative Spin-Flip Configuration Interaction (SF-CI) method is proposed that addresses and corrects the spin contamination issues inherent in SF methods. This is done by implementing SF within the ORMAS-CI algorithm as developed by Ivanic in 2003. This approach is general, and can be used to carry out any number spin-flipping excitations, as well as include additional configurations into the CI calculation. This method is applied to successfully study multiple-bond breaking processes (HF, F2, N2) and photochemical reactions involving conical intersections (ethylene, azomethane). Dynamic correlation is accounted for via perturbation theory in the form of a doubles correction. Analytic gradients are implemented for geometry optimizations and solvent effects included via the Effective Fragment Potential (EFP) method.

Introducing a general spin-correct spin-flip configuration interaction method that includes dynamic correlation

253rd National Meeting (2017)

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