Francis Muguet recommended: > R. McWeeny > Methods of Molecular Quantum Mechanics > (2nd Ed) Academic Press (1989). > ISBN 0-12-486551-8 > The price tag ($140) is quite high however There is also a cheaper paperback edition available, ISBN 0-12-486552-6. Ross Dickson (dickson "at@at" zinc.chem.ucalgary.ca)