title: A Lanczos-chain driven approach for calculating damped vibrational configuration interaction response functions.
abstract: We present an approach based on the Lanczos method for calculating the vibrational configuration interaction response functions necessary for evaluating the pure vibrational contributions to the polarizabilities and first hyperpolarizabilities of molecules. The method iteratively builds a tridiagonal representation of the central response matrix, which is subsequently used for solving the response equations. From the same chain, the response functions can be evaluated approximately for any frequency as well as using any complex damping factor. Applications to formaldehyde, cyclopropene, and uracil illustrate the concepts presented.
authors.affiliation: Department of Chemistry, The Lundbeck Foundation Center for Theoretical Chemistry and Center for Oxygen Microscopy and Imaging, University of Aarhus, Langelandsgade 140, DK-8000 Aarhus C, Denmark. mbh@chem.au.dk
authors.forename: Mikkel Bo
authors.initials: MB
authors.lastname: Hansen
authors.forename: Peter
authors.initials: P
authors.lastname: Seidler
authors.forename: Werner
authors.initials: W
authors.lastname: Gyorffy
authors.forename: Ove
authors.initials: O
authors.lastname: Christiansen