Surplus function variational quantum Monte Carlo approach: Excited state processing

Surplus function variational quantum Monte Carlo approach used for the excited state of electrons has been proposed. If the initial wave functions of both the excited state and ground state belong to the irreducible representation with different symmetries, the surplus function variational quantum Monte Carlo approach of the excited state is identical to that of the ground state, and if they belong to the irreducible representation with an identical symmetry, the surplus function variational quantum Monte Carlo approach of the ground state can also be applied to the excited state only by orthogonal revision for the initial wave function of the excited state. The detailed calculations formulas on the surplus function variational quantum Monte Carlo approach of the excited state have been deduced. A complete set of the surplus function variational quantum Monte Carlo approach for both the ground state and excited state has been established. The energy values of X 3B1, 1 1A1, and 2 1A1 states of CH2 have bee...