Self-consistent field treatment and analytical energy gradient of local response dispersion method

This study presents the self-consistent field (SCF) treatment of the local response dispersion (LRD) method. The implementation of SCF involves the modification of the Kohn-Sham Fock matrix by adding the dispersion potential. The derivatives of atomic pseudo-polarizabilities with respect to the density variables, which are required for evaluating the dispersion potential, are efficiently updated in the SCF procedure. Analytical energy gradient of the LRD method is also developed based on the SCF treatment. Numerical assessments of the present treatment clarified that the SCF effect brings about minor changes in both energy and electronic structure. The computational time, and number of SCF iterations, are essentially unaffected by moving from a non-self-consistent implementation to a self-consistent one. For the geometry optimizations for weakly interacting systems, the inclusion of the LRD energy gradients is shown to be essential for accurately demonstrating the intermolecular geometric parameters.