Using Carlsson's approach of the low-order moments approximation to tight binding, we develop improved potentials for Mo and W, also a potential for V. This model was fit to twelve bulk properties, namely cohesive energy, lattice constant, elastic constants, vacancy properties, bcc - fcc and bcc - A15 structural energy differences and four zone edge phonons. Also, for Mo and W, the functions were required to yield a reconstruction of the (100) surface, although the details of the surface were not fit. The potentials were tested by calculating surface properties. Most importantly, both the W(100) (√2 × √2 )R45° and Mo(100) c(7√2 × √2 )R45° surface reconstructions are observed, which is a good indication of the physical correctness of the angular terms, although for Mo(100) the lowest energy occurred on c(5√2 × √2 )R45° structure.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Condensed Matter Physics
- Surfaces and Interfaces