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Features

eFF is a force field that contains electrons. Nuclei are represented by point charges, and electrons by spherical Gaussian wave packets whose position and size can vary, and which can be tagged with either an up or down spin. The particles interact via an effective potential that is a sum of electron kinetic energies, electrostatic interactions, and Pauli repulsion. This version of eFF gives a reasonable description of systems containing nuclei from Z=1-6.

To compute the ground state, we minimize the energy of the system, optimizing the nuclear and electron positions and the electron sizes simultaneously. To simulate materials at finite temperatures, including nonadiabatic excited electron dynamics, we propagate semiclassical Ehrenfest dynamics, allowing the positions of the nuclei and electrons, as well as the sizes of the electrons, to change with time.

The eFF program has the following features:

We have included several supporting programs. The eFFview visualizer makes it easy to generate high quality still frames and movies of nuclear and electron dynamics from eFF input and output files. Builder scripts such as xyz2cfg, diamond_cfg, beryllium_cfg, etc. can be run to create a wide variety of molecules and periodic extended structures for simulation with eFF (Chapter 5).


next up previous contents index
Next: Installation Up: Introduction Previous: Introduction   Contents   Index
Julius 2008-04-29