| 1 | Author
| M. Weisser, W. Weyrich | Requires cookie* | | Title
| The Electronic Structure of Hydrogen Bonding in a-Oxalic Acid Dihydrate  | | | Abstract
| Compton spectra of a-oxalic acid dihydrate single-crystal slices and powder samples were mea-sured in a helium atmosphere using 59.537 keV 241 Am radiation. In the anisotropic case, the scattering vector was oriented parallel to the shortest hydrogen bond, in the direction of the C = O bond, parallel to the C — O bond and perpendicular to the (a, c)-plane. The comparison of theoretical reciprocal form factors, calculated with a local density-approximation (LDA) method for an a-(COOH) 2 • 2H 2 0 cluster in triple-zeta basis-set quality, with the experimental data has demon-strated that there is a considerable influence of intermolecular interactions on the electronic struc-ture. Further calculations including the intermolecular interactions of the first coordination sphere by symmetrical orthogonalisation of the LDA wave functions clearly improved the agreement of experiment and theory. A theoretical analysis of the reciprocal form factor B a (s) in the direction of the three different hydrogen bonds of a-oxalic acid dihydrate on the basis of the cluster calculations has shown that in the region above s = 1.9 Ä all these bonds are dominated by electrostatic attrac-tion and exchange repulsion of the donor and the acceptor system. | | |
Reference
| Z. Naturforsch. 48a, 315—324 (1993); received January 28 1993 | | |
Published
| 1993 | | |
Keywords
| a-Oxalic acid dihydrate, Compton spectroscopy, Hydrogen bonding, Reciprocal form factor, Density functional calculations | | |
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| default:Reihe_A/48/ZNA-1993-48a-0315.pdf | | | Identifier
| ZNA-1993-48a-0315 | | | Volume
| 48 | |
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