Calculations of bandstructure of intermetallic compounds using the multiple scattering Xα cluster method and k dependent boundary conditions

The spherical Wigner-Seitz boundary condition (1933, 1934) for approximately treating electronic states in solids by atomic calculations can be readily extended to include molecular clusters. If, in addition, matching conditions for cluster wavefunctions at the outer sphere radius R are taken to be wavevector dependent, some approximate representation of the energy bands E_n(k) is obtained. The self-consistent multiple scattering (SCMS) X alpha method with modified boundary conditions has been applied to calculations of the electronic structure of Cu metal and Al₂Au and Al ₂Cu alloys. The results for Cu agree well with SC X alpha bandstructures, as to bandwidths and positions, giving quite reasonable density of states (DOS) curves. The cluster DOS are compared with X-ray emission and photoelectron (ESCA) spectra of the alloys. The results show that the model can describe the main features of electronic structure of intermetallic compounds, with very little computational effort.