AN IMPROVED APPROACH TO SELF-CONSISTENT DIAGONALIZATION-FREE TOTAL-ENERGY MINIMIZATIONS FOR METALS

An improved method for the ab initio total-energy minimization and molecular-dynamics simulation of metallic systems is presented. In this method, the problem of fluctuating occupation numbers is dealt with in a new way. Proceeding from the steepest-descent ansatz, an iteration equation is derived which has the following important features: No re-orthonormalization of wave functions is needed after each iteration step, fluctuating occupation numbers are explicitly allowed, and no diagonalization of a Hamiltonian or Lagrange matrix is required. Furthermore, our method is especially suited for atom-centered basis functions.