DIAGONALIZATION FREE IMPLEMENTATION OF KOHN-SHAM EQUATIONS WITH LOCALIZED BASIS-SETS

A new strategy to solve the Kohn-Sham equations of density functional theory is presented which avoids diagonalization within a finite basis -set expansion. The implementation is based on an expansion of orbital s in terms of Gaussian functions and it is shown that the algorithm is competitive with more conventional approaches. The new approach is ba sed on conjugated gradients optimization augmented by an approximate s econd-order update together with convergence acceleration. Computation al advantages of the new algorithm are discussed under the special asp ect of parallel computing. (C) 1997 John Wiley & Sons, Inc.