THE APPLICABILITY OF SCALING LAWS IN TIGHT-BINDING MOLECULAR-DYNAMICS

We test the validity of the scaling schemes which are frequently used in computer simulations using Molecular Dynamics in order to scale the tight-binding (TB) matrix elements (of Slater and Koster type) with the interatomic distance. In particular, we calculate. TB parameters of Si for various interatomic distances and enviroments by performing total energy restricted Hartree-Fock calculations for the Si2H6 and Si8H18 clusters. It is demonstrated that the scaling of the TB parameters with the interatomic distance is a very sensitive process with a strong many-body character. On the other hand, the present calculations indicate that cluster calculations can provide an effective mean for obtaining an accurate scaling of the TB matrix elements which can be in the form of an exponential function.