A Fast Split-Operator Spectral Method for Solving the Time-Dependent Schrödinger Equation in Angular Coordinates

An efficient split-operator technique for solving the time-dependent Schrödinger equation with angular variables is presented, where a fast spherical harmonics transform accelerates the transformations between angle and angular momentum representations. Unlike previous techniques, this method demonstrates adaptive time stepping, facile inclusion of azimuthal asymmetries, and favorable scaling while avoiding the need for both kinetic and potential energy matrix elements. Several examples are presented.