Capturing multireference excited states by constrained-density-functional theory
Abstract
The computation of excited electronic states with commonly employed (approximate) methods is challenging, typically yielding states of lower quality than the corresponding ground state for a higher computational cost. In this work, we present a mean-field method that extends the previously proposed excited constrained-density-functional theory (XCDFT) from single Slater determinants to ensemble one-body reduced density matrices for computing low-lying excited states. The method still retains an associated computational complexity comparable to a semilocal density functional theory (DFT) calculation while at the same time it is capable of approaching states with multireference character. We benchmark the quality of this method on well-established test sets, finding good descriptions of the electronic structure of multireference states and maintaining an overall accuracy for the predicted excitation energies comparable to semilocal time-dependent DFT.
- Publication:
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Physical Review A
- Pub Date:
- March 2020
- DOI:
- 10.1103/PhysRevA.101.032510
- arXiv:
- arXiv:1911.01570
- Bibcode:
- 2020PhRvA.101c2510K
- Keywords:
-
- Condensed Matter - Materials Science;
- Physics - Chemical Physics
- E-Print:
- Phys. Rev. A 101, 032510 (2020)