This is the one-electron analogue of the time-dependent Schrödinger equation and the Fock operator F functions as the effective Hamiltonian. The equation of motion for each ψ k is numerically integrated to obtain time-evolving MOs ψ k (r, t), starting from ground-state MOs at t = 0. The functions ψ k (r, 0) are eigenfunctions of F . Equation ( ) is equivalent to the Liouville-von Neumann equation