The internal rotation of 2,2Ј-bithiophene was investigated within the Ž . density functional theory DFT approach. Fully optimized DFT torsional potentials are Ž . compared with Møller᎐Plesset MP2 results which predict a fourfold potential with s-cis-and s-trans-gauche minima. DFT calculations fail i
The performance of density functional methods for the description of weak interaction potentials. The torsional potential of butane
✍ Scribed by Ursula Röthlisberger; Michael L. Klein
- Publisher
- Elsevier Science
- Year
- 1994
- Tongue
- English
- Weight
- 526 KB
- Volume
- 227
- Category
- Article
- ISSN
- 0009-2614
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✦ Synopsis
The torsional potential about the central C-C bond in n-butane was investigated as a test case to probe the capability of density functional methods for the description of weak interaction potentials. Calculations were performed within the local density approximation as well as with gradient corrected models. Apart from a slight underestimation of the gauche-trans energy difference (AEor=O.4-0.5 kcal/mol) the local density approximation generates a potential energy surface in excellent agreement with the most elaborate correlated quantum-chemical methods currently available. The inclusion of gradient corrections compensates the underestimation of the gauche-trans energy difference (A&r= 0.8-0.9 kcal/mol).
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