Computing the superexchange electronic factor of electron transfer theory using a grid-based numerical method

We report a method for calculating the electronic factor in the superexchan ge rate equation of electron transfer theory; this method is a basis set in dependent, grid-based numerical technique that utilizes fast Fourier transf orms (FFTs) and a Lanczos recursion in a pseudospectral framework and is us ed to treat a three-dimensional one-electron model of the electronic factor . We compare eigenvalues calculated from the current method to eigenvalues from the literature for both one-dimensional (1D) and three-dimensional (3D ) model problems and find that the current method provides excellent accura cy and efficiency. With respect to the superexchange electronic factor, we use model potentials to calculate the tunneling matrix elements with the pr esent method to illustrate how the method can be used to address current is sues in superexchange. In particular, we show how this method is useful in evaluating the effect of the bridge potential on the superexchange electron ic factor when using repulsive-core pseudopotentials to represent the bridg e. (C) 2000 John Wiley & Sons, Inc.