Abstract
The response of an atomic or molecular system to an external perturbation is studied within the framework of time-dependent Hartree-Fock theory. Quadratic response functions are defined and analyzed with regard to their poles and residues, from which an expression for matrix elements of an arbitrary operator between excited states is deduced. For one-particle operators the matrix elements $〈m|A|n〉$ are correct through first order in correlation and the hypervirial relation $({E}_{n}\ensuremath{-}{E}_{m}) 〈m|A|n〉=〈m|[A,H]|n〉$ is satisfied. Spurious poles, which have no counterpart in an exact theory, are encountered in the quadratic response functions. Their appearance is attributed to well-known deficiencies in the time-dependent Hartree-Fock approximation.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
