Analytic energy gradients for constrained DFT-configuration interaction
Author(s)Kaduk, Benjamin James; Tsuchimochi, Takashi; Van Voorhis, Troy
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The constrained density functional theory-configuration interaction (CDFT-CI) method has previously been used to calculate ground-state energies and barrier heights, and to describe electronic excited states, in particular conical intersections. However, the method has been limited to evaluating the electronic energy at just a single nuclear configuration, with the gradient of the energy being available only via finite difference. In this paper, we present analytic gradients of the CDFT-CI energy with respect to nuclear coordinates, which gives the potential for accurate geometry optimization and molecular dynamics on both the ground and excited electronic states, a realm which is currently quite challenging for electronic structure theory. We report the performance of CDFT-CI geometry optimization for representative reaction transition states as well as molecules in an excited state. The overall accuracy of CDFT-CI for computing barrier heights is essentially unchanged whether the energies are evaluated at geometries obtained from quadratic configuration-interaction singles and doubles (QCISD) or CDFT-CI, indicating that CDFT-CI produces very good reaction transition states. These results open up tantalizing possibilities for future work on excited states.
DepartmentMassachusetts Institute of Technology. Department of Chemistry
The Journal of Chemical Physics
American Institute of Physics (AIP)
Kaduk, Benjamin, Takashi Tsuchimochi, and Troy Van Voorhis. “Analytic Energy Gradients for Constrained DFT-Configuration Interaction.” The Journal of Chemical Physics 140, no. 18 (May 14, 2014): 18A503.
Author's final manuscript