Tucker Carrington Jr.

Departement de chimie, Universite de Montreal,  Case postale 6128, succursale Centre-ville, Montreal (Quebec) H3C 3J7, CANADA
 

We present an efficient iterative method for calculating energy levels and wavefunctions.  The method requires storing only a small number of vectors but allows one to calculate energy levels and wavefunctions with fewer matrix-vector products than the filter diagonalisation method of Mandelshtam and Taylor. A zeroth-order Hamiltonian is used to precondition a spectral transform Lanczos method.