Performance of time-dependent density functional and Green functions methods for calculations of excitation energies in radicals and for Rydberg electronic states
Copyright 2003 Wiley Periodicals, Inc. J Comput Chem 24: 692-700, 2003
| Veröffentlicht in: | Journal of computational chemistry. - 1984. - 24(2003), 6 vom: 30. Apr., Seite 692-700 |
|---|---|
| 1. Verfasser: | |
| Weitere Verfasser: | |
| Format: | Aufsatz |
| Sprache: | English |
| Veröffentlicht: |
2003
|
| Zugriff auf das übergeordnete Werk: | Journal of computational chemistry |
| Schlagworte: | Journal Article |
| Zusammenfassung: | Copyright 2003 Wiley Periodicals, Inc. J Comput Chem 24: 692-700, 2003 Time-dependent density functional (TD-DFT) and perturbation theory-based outer valence Green functions (OVGF) methods have been tested for calculations of excitation energies for a set of radicals, molecules, and model clusters simulating points defects in silica. The results show that the TD-DFT approach may give unreliable results not only for diffuse Rydberg states, but also for electronic states involving transitions between MOs localized in two remote from each other spatial regions, for example, for charge-transfer excitations. For the. O-SiX(3) clusters, where X is a single-valence group, TD-DFT predicts reasonable excitation energies but incorrect sequence of electronic transitions. For a number of cases where TD-DFT is shown to be unreliable, the OVGF approach can provide better estimates of excitation energies, but this method also is not expected to perform universally well. The OVGF performance is demonstrated to be satisfactory for excitations with predominantly single-determinant wave functions where the deviations of the calculated energies from experiment should not exceed 0.1-0.3 eV. However, for more complicated transitions involving multiple bonds or for excited states with multireference wave functions the OVGF approach is less reliable and error in the computed energies can reach 0.5-1 eV |
|---|---|
| Beschreibung: | Date Completed 28.10.2003 Date Revised 31.03.2003 published: Print Citation Status PubMed-not-MEDLINE |
| ISSN: | 1096-987X |