| Autor: |
Adya, Ashok K., Kalugin, Oleg N., Volobuev, Maxim N., Kolesnik, Yaroslav V. |
| Předmět: |
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| Zdroj: |
Molecular Physics; 05/20/2001, Vol. 99 Issue 10, p835-854, 20p |
| Abstrakt: |
Molecular dynamics (MD) simulations of pure dimethyl sulphoxide (DMSO) and solutions of Na[sup +], Ca2[sup +], Cl[sup -], NaCl and CaCl[sup 2] in DMSO have been performed at 298.15 K and 398.15 K in NVT ensembles by using a four-interaction-site model of DMSO and reaction field method for Coulombic interactions. The structure of solvent, ion-solvation shells and ion-pairs have been analysed by employing a concept of coordination centres and characteristic vectors of the solvent molecule. Results are given for atom-atom (corresponding to DMSO), ion-atom and ion-ion radial distribution functions (RDFs), orientation of the DMSO molecules and their geometrical arrangements in the first solvation shells of the ions (Na[sup +], Ca[sup 2+], Cl[sup -]). A preferential formation of cyclic dimers with antiparallel alignment between dipole moments of nearest-neighbour molecules in the pure solvent is found. Geometrical models of the first coordination shells of the ions in 'infinitely dilute solutions' are proposed. Ion-ion RDFs in NaCl-DMSO and CaCl\[sup 2]-DMSO solutions reveal the presence of both solvent separated (SSIP) and contact (CIP) ion pairs. The structures of the solvation shells of such ion pairs are also discussed. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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