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Isotope effect in dihydrogen-bonded systems: application of the analytical energy gradient method in the nuclear orbital plus molecular orbital theory.
- Source :
-
Molecular Physics . 10/10/2007, Vol. 105 Issue 19-22, p2649-2657. 9p. 1 Diagram, 3 Charts, 1 Graph. - Publication Year :
- 2007
-
Abstract
- We investigate isotope effects in dihydrogen systems using the nuclear orbital plus molecular orbital (NOMO) theory, which simultaneously determines nuclear and electronic wave functions without the Born-Oppenheimer approximation. In order to estimate the vibrational averaging bond distances, the analytical energy gradients are used for the NOMO theory. The bond distances of three dihydrogen-bonded systems, namely H3NX+ ··· XBeH, LiX ··· XC2H and H2BX ··· XF for X = H, D and T, are obtained. The X ··· X bond distances decrease with respect to the substitution T → D → H, which is contrary to the behaviour of typical hydrogen bonds. This indicates that isotope effects strengthen the X ··· X bond. This behaviour is analogous to the Ubbelohde effect observed in the solid phase. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 00268976
- Volume :
- 105
- Issue :
- 19-22
- Database :
- Academic Search Index
- Journal :
- Molecular Physics
- Publication Type :
- Academic Journal
- Accession number :
- 27950067
- Full Text :
- https://doi.org/10.1080/00268970701618416