Analytic Evaluation of Energy First Derivatives for Cholesky Decomposition-Based Relativistic Two-Component Coupled-Cluster Methods

Analytic
evaluation of first-order properties for the Cholesky
decomposition (CD)-based relativistic two-component coupled-cluster
singles and doubles (CCSD) and equation-of-motion CCSD (EOM-CCSD)
methods is reported. The CD-based implementation significantly improves
the efficiency in handling two-electron integrals involving frozen
orbitals and reduces the storage requirement for the two-electron
density matrices in analytic derivative calculations. Benchmark calculations
of dipole moments, electric field gradients, and molecular sensitivity
factors for nuclear Schiff moments show that a modest Cholesky threshold
of 10–4 provides accurate results. Calculations
for Mössbauer spectroscopy parameters of gold-containing complexes
are reported to demonstrate the applicability of the present implementation
to medium-sized molecules containing heavy atoms.