Variational principles for the time-independent wave-packet-Schrödinger and wave-packet-Lippmann–Schwinger equations

Abstract

Several variational principles, whose Euler equations are the recently derived time-independent wave-packet-Schrödinger or wave-packet-Lippmann–Schwinger equations, are presented. A particularly attractive wave-packet-Kohn variational principle for either the T- or S-matrix is given which yields inhomogeneous algebraic equations whose ‘‘universal inhomogeneity’’ does not depend explicitly on the collision energy. The validity of the approach is demonstrated with calculations for two simple one dimensional scattering problems and for the collinear H+H2 reactive scattering problem.