Communication: Automatic code generation enables nuclear gradient computations for fully internally contracted multireference theory
Abstract
Analytical nuclear gradients for fully internally contracted complete active space second-order perturbation theory (CASPT2) are reported. This implementation has been realized by an automated code generator that can handle spin-free formulas for the CASPT2 energy and its derivatives with respect to variations of molecular orbitals and reference coefficients. The underlying complete active space self-consistent field and the so-called Z-vector equations are solved using density fitting. The implementation has been applied to the vertical and adiabatic ionization potentials of the porphin molecule to illustrate its capability.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Feb 05, 2015
- Source ID
- 10.1063/1.4907717
Entities
People
- Matthew K. Macleod
- Toru Shiozaki
Organizations
- Air Force Office of Scientific Research
- Northwestern University
- United States Department of Energy