Abstract
A tight-binding calculation of the local density of electronic states in b.c.c., amorphous and liquid iron is carried out by using two different methods: the recursion method proposed by Haydock, Heine and Kelly (1972, 1975) and the equation-of-motion technique. The two methods are found to yield similar results, but the recursion method is found to be considerably faster. It is concluded that unless the local density of states (DOS) curve is particularly featureless, the equation-of-motion technique will require a computation time an order of magnitude larger than the recursion method for systems with ∼ 1000 degrees of freedom. A discussion of the relative merits of these methods is presented.