Favorable performance of the DFT methods in predicting the minimum-energy structure of the lowest triplet state of WF{sub 4}
- Pacific Northwest National Lab., Richland, WA (United States)
The tetrahedral structure of the lowest triplet state of the WF{sub 4} complex was examined using different variants of the density functional theory (DFT) and conventional ab initio methods. The low-level, conventional, ab initio methods, such as SCF, MP2, MP3, and CISD, predict the tetrahedral structure to be a minimum, whereas the DFT schemes predict an imaginary frequency for the e vibrational mode. Only after recovering electron correlation effects at the MP4 and higher levels, the conventional electronic structure methods also predict the T{sub d} structure to be a second-order stationary point. This is not the correlation but the exchange part of the DFT functionals which is responsible for the discrepancy between the DFT and low-level, conventional, ab initio predictions. The lowering of symmetry to C{sub 2v} leads to a minimum on the lowest triplet potential energy surface and the electronic energy difference between the T{sub d} and C{sub 2v} stationary points amounts to 0.85 and 0.96 kcal/mol at the B3LYP and CCSD(T) levels, respectively.
- Sponsoring Organization:
- USDOE, Washington, DC (United States); National Science Foundation, Washington, DC (United States)
- DOE Contract Number:
- AC06-76RL01830
- OSTI ID:
- 357656
- Journal Information:
- International Journal of Quantum Chemistry, Vol. 73, Issue 4; Other Information: PBD: 15 Jun 1999
- Country of Publication:
- United States
- Language:
- English
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