화학공학소재연구정보센터
Chemical Physics Letters, Vol.639, 315-319, 2015
The one-electron description of excited states: Natural excitation orbitals of density matrix theory and Kohn-Sham orbitals of density functional theory as ideal orbitals
Linear response density matrix functional theory has been shown to solve the main problems of time-dependent density functional theory (deficient in case of double, charge transfer and bond breaking excitations). However, the natural orbitals preclude the description of excitations as (approximately) simple orbital-to-orbital transitions: many weakly occupied 'Virtual' natural orbitals are required to describe the excitations. Kohn-Sham orbitals on the other hand afford for many excitations such a simple orbital description. In this communication we show that a transformation of the set of weakly occupied NOs can be defined such that the resulting natural excitation orbitals (NEOs) restore the single orbital transition structure for excitations generated by the linear response DMFT formalism. (C) 2015 Elsevier B.V. All rights reserved.