We consider many-body effects on the band structure of solid argon within the Coulomb-hole—plus—screened-exchange approximation, and with the use of a basis set of orthogonalized plane waves. The difficulties inherent to the nonlocal character of the self-energy operator are over-come by expressing the crystal density matrix in terms of localized Gaussian functions. A major advantage of this technique is that all the matrix elements necessary to perform the correlated band-structure calculation can be computed analytically. Our results for the case of argon are compared with experiments and with previous theoretical works.
