화학공학소재연구정보센터
Chemical Physics Letters, Vol.455, No.1-3, 124-130, 2008
Hartree-Fock and standard density functional theory methods applied to excited states: The case of NO2
It has been shown that energies and geometries of lowest and higher excited states of symmetric molecules can be calculated with reasonable accuracy by Hartree-Fock (HF) and standard (time-independent) density functional theory (DFT) methods. In the example of NO2, the geometries of 15 excited doublet states in C-2 nu symmetry, (1-5)(2)A(2), (1-5)B-2(1), and (1-5)B-2(2) were optimized by UHF and DFT (UB3PW91) with a 6-311+G(3df) basis set, all resulting from single excitations with respect to the (2)A(1) ground state. Energies and optimized geometries compare well with available literature values. Vertical HF and DFT excitation energies for these states have been compared with multireference configuration interaction and time-dependent DFT values. Examples of DFT optimized doubly and triply excited doublet states are given. (C) 2008 Elsevier B.V. All rights reserved.