The implementation of a self-consistent constricted variational density functional theory for the description of excited states

• Published in: The Journal of chemical physics 2012-03, Vol.136 (12), p.124107-124107-10
• Main Authors: Ziegler, Tom, Krykunov, Mykhaylo, Cullen, John
• Format: Article
• Language: English
• Subjects: Theoretical Methods and Algorithms
• ISSN: 0021-9606; 1089-7690
• DOI: 10.1063/1.3696967

We present here the implementation of a self-consistent approach to the calculation of excitation energies within regular Kohn-Sham density functional theory. The method is based on the n-order constricted variational density functional theory (CV(n)-DFT) [ T. Ziegler , M. Seth , M. Krykunov , J. Autschbach , and F. Wang , J. Chem. Phys. 130 , 154102 ( 2009 )] 10.1063/1.3114988 and its self-consistent formulation (SCF-CV(∞)-DFT) [ J. Cullen , M. Krykunov , and T. Ziegler , Chem. Phys. 391 , 11 ( 2011 )] 10.1016/j.chemphys.2011.05.021 . A full account is given of the way in which SCF-CV(∞)-DFT is implemented. The SCF-CV(∞)-DFT scheme is further applied to transitions from occupied π orbitals to virtual π * orbitals. The same series of transitions has been studied previously by high-level ab initio methods. We compare here the performance of SCF-CV(∞)-DFT to that of time dependent density functional theory (TD-DFT), CV(n)-DFT and ΔSCF-DFT, with the ab initio results as a benchmark standard. It is finally demonstrated how adiabatic TD-DFT and ΔSCF-DFT are related through different approximations to SCF-CV(∞)-DFT.