Excited States of H_2O using improved virtual orbitals

A technique for solving the Hartree-Fock equations is proposed which has the property that the virtual orbitals from the ground state wavefunction are variationally correct approximations to the self-consistent orbitals for the excited states. This allows a whole series of excited wavefunctions to be obtained from one calculation. This method was applied to a number of low-lying singlet and triplet excited states of H2O, and found to lead to good results