A statistical multireference state-specific dressing of configuration interaction matrices: application to Heisenberg Hamiltonians

Abstract

For an arbitrary (truncated or selected) configuration interaction (CI) space and from a specific eigenvector, one may extract statistical and state specific amplitudes of elementary excitations. These amplitudes are used for the evaluation of the coefficients of the outer-space determinants, leading to a state specific dressing of the CI matrix. The process is repeated to self-consistency. Numerical applications to ground and excited states of a Heisenberg Hamiltonian for conjugated molecules illustrate the efficiency of the method.