We present an implementation of coupled-perturbed complete active space self-consistent field (CP-CASSCF) theory for the computation of nuclear magnetic resonance chemical shifts using gauge-including atomic orbitals and Cholesky decomposed two-electron integrals. The CP-CASSCF equations are solved using a direct algorithm where the magnetic Hessian matrix–vector product is expressed in terms of one-index transformed quantities. Numerical tests on systems with up to about 1300 basis functions provide information regarding both the computational efficiency and limitations of our implementation.
Nottoli, T.; Burger, S.; Stopkowicz, S.; Gauss, J. & Lipparini, F.
J. Chem. Phys. 157, 084122 (2022) https://doi.org/10.1063/5.0101838
