Application of polynomial functions in calculations of optical susceptibilities of atoms and molecules by the Floquet method

The role of polynomial terms included in trial many-electron wave functions for variational calculations of the dynamic polarizabilities and hyperpola rizabilities of atoms and molecules in the Floquet theory is examined. The role of these terms is found to be very significant, and, in particular, po lynomials of the first order are important in calculating the linear polari zability. To obtain more reliable results in calculating the hyperpolarizab ilites, it is necessary to include polynomials of higher orders. (C) 2001 M AIK "Nauka/Interperiodica".