A method for ab initio nonlinear electron-density evolution

A numerical method is given for effecting nonlinear local density functiona l evolution. Within a given time interval, Chebyshev quadrature points are used to sample the evolving orbitals. An implicit equation coupling wave fu nctions at the different time points is then set up. The equation is solved iteratively using the "direct inversion in iterative space" acceleration t echnique. Spatially, the orbitals are represented on a Fourier grid combine d with soft pseudopotentials. The method is first applied to the computatio n of the (3)Pi (g) adiabatic potential energy curves of Al-2. Next, the ele ctronic dynamics of a toy molecular wire is studied. The wire consists of a C2H4 molecule connected via sulfur atoms to two gold atoms, the "electrode s." The molecule is placed in a homogeneous electric field and a dynamical process of charge transfer is observed. By comparing the transient with tha t of a resistance-capacitance circuit, an effective Ohmic resistance and ca pacitance is estimated for the system. (C) 2001 American Institute of Physi cs.