Direct molecular dynamics using quantum chemical hamiltonians: C-60 impacton a passive surface

Quantum chemical Hamiltonians of the semiempirical type potentially provide a more reliable description of a potential energy surface for large scale molecular dynamics than does the tight-binding (TB) Hamiltonian, a reparame trized extended Huckel Hamiltonian including a short range repulsion. Their performance is tested here and compared with results from TB simulations. The methods considered are from the zero differential overlap family of sem iempirical Hamiltonians, these are the intermediate neglect of differential overlap (INDO) method and three parametrizations of the neglect of differe ntial diatomic overlap (NDDO) method, AMI, PM3, and MNDO. The collision of the C-60 molecule with a passive surface at two collision energies is the t est problem, where the higher energy leads to shattering of the molecule. T he NDDO Hamiltonians are found to give a better qualitative description tha n the INDO Hamiltonian at both energies and further studies to reparametriz e the NDDO form for direct MD are indicated.