Ab initio SCF and mølleb-plesset calculations on the hydrogen bond in hydrogen malonate: effects of neighbour ions and polarizable medium
| Autor: | J. Mavri, D. Hadži, M. Hodošček |
|---|---|
| Rok vydání: | 1990 |
| Předmět: |
Hydrogen
Hydrogen bond Chemistry Gaussian orbital Solvation Ab initio chemistry.chemical_element Condensed Matter Physics Biochemistry chemistry.chemical_compound Malonate Computational chemistry Intramolecular force Rectangular potential barrier Physical chemistry Physical and Theoretical Chemistry |
| Zdroj: | Journal of Molecular Structure: THEOCHEM. 209:421-431 |
| ISSN: | 0166-1280 |
| DOI: | 10.1016/0166-1280(90)80093-4 |
| Popis: | Energy calculations at the SCF level with full geometry optimization and constraint to C 2v symmetry were done on hydrogen malonate using the MINI-1, 4-31G, 4-31 (+)G, 6-31 + + G, 6-31G ∗∗ and 6–31 + + G ∗∗ basis sets. The energy differences between both forms, indicative of the adiabatic potential barrier, are in the region of 2 kcal mol −1 and thus in favour of the asymmetrically placed proton, except for the calculation using the minimal base. Correction for correlation at the MP2 level, applied to the SCF calculated geometries, lowers the potential barrier. Nonadiabatic barriers at the HF level are substantially higher. Lithium ions placed 3 A and 5 A from the carboxyl groups induce a difference of ca. 19 kcal mol −1 between the two proton positions. The potential barrier is raised by the effect of the solvent cavity. This effect stabilizes by 7.75 kcal mol −1 the conformation with one carboxylic group perpendicular to the other relative to one with the intramolecular hydrogen bond. |
| Databáze: | OpenAIRE |
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