CALCULATING THE DENSITY-OF-STATES AND THE LINEAR-RESPONSE FUNCTIONS WITH TIME-DEPENDENT SCHROEDINGER EQUATIONS

An O(N) algorithm is proposed for calculating the density of states an d the linear response functions of noninteracting electrons. This algo rithm is simple and suitable to parallel- and vector-computation. Sinc e it avoids O(N-3) computational effort of matrix diagonalization, it requires only O(N) computational efforts where N is the dimension of t he statevector. The use of this O(N) algorithm is very effective since otherwise we have to calculate a large number of eigenstates, i.e. th e occupied one-electron states up to the Fermi energy and the unoccupi ed states with higher energy. The advantage of this method compared to the Chebyshev polynomial method recently developed by Wang [27,28] is that our method can calculate linear response functions without any s torage of huge statevectors on external storage. (C) 1998 Elsevier Sci ence B.V. All rights reserved.