Environment-dependent tight-binding model for molybdenum

A transferable orthogonal tight-binding model is developed for molybdenum, with special emphasis on applications in molecular-dynamics studies. The elements of the Hamiltonian matrix and the repulsive potential are allowed to depend on the environment in order to account for the effects of the neglected three-center matrix elements, for the neglected nonorthogonality effects and for the variation of the finite set of basis orbitals in different configurations as well. To check the accuracy of the model, the structural energy differences, the elastic constants, the phonon spectrum along high-symmetry lines in the Brillouin zone, the formation and migration energy of a vacancy, the formation energy of an octahedral interstitial atom, surface energies, and relaxations, as well as reconstructions of a (100) surface, are calculated and compared with ab initio data and experimental results.