Experimentally constrained molecular relaxation : The case of glassy GeSe 2

An ideal atomistic model of a disordered material should contradict no experiments, and should also be consistent with accurate force fields seither ab initio or empiricald. We make significant progress toward jointly satisfying both of these criteria using a hybrid reverse Monte Carlo approach in conjunction with approximate first-principles molecular dynamics. We illustrate the method by studying the complex binary glassy material g-GeSe2. By constraining the model to agree with partial structure factors and ab initio simulation, we obtain a 647-atom model in close agreement with experiment, including the first sharp diffraction peak in the static structure factor. We compute the electronic state densities and compare to photoelectron spectroscopies. The approach is general and flexible.