39.1.5 State-averaged MCSCF gradients with SEWARD

SA-MCSCF gradients can be computed using segmented or generally contracted basis sets using SEWARD and the RS2 gradient program. The NOEXC directive has to be used in the RS2 input, but no CPMCSCF card is required in MULTI. The RS2 gradient program does the CP-MCSCF automatically.

Example: compute SA-CASSCF gradients for $^2\Pi$ and $^2\Sigma^+$ state of OH.

oh_samcforce.com

Without the NOEXC directive, the RS2 (CASPT2) gradient would be evaluated, using the state-averaged orbitals.