4TH ORDER TIME-DEPENDENT VARIATION PERTURBATION-THEORY BASED ON THE HYDRODYNAMIC ANALOGY

The hydrodynamic analogy to quantum mechanics ansatz for the total wavefunction and the Frenkel variational principle are used to determine a functional, through fourth order, which describes the response of a system under the influence of a time-dependent electric field. The fourth order functional is shown to provide an improvable upper bound and it is shown to be formally equivalent to the approach formulated by Karplus and Kolker. © 1979 Taylor and Francis Ltd.