Analytic properties of connected moments expansions

The derivation of the connected moments expansion (CMX) is examined as well as the singularities that arise in the series expansion for the ground-state energy. Explicit analytic results are presented that show a canceling of these singularities. Also, an alternate moments expansion (AMX) is derived that closely models the CMX but displays a varied computational range. © 1994 John Wiley & Sons, Inc.