Buntkowsky, G. ; Limbach, H. H. ; Walaszek, B. ; Adamczyk, A. ; Xu, Y. ; Breitzke, H. ; Schweitzer, A. ; Gutmann, T. ; Wächtler, M. ; Frydel, J. ; Emmler, T. ; Amadeu, N. ; Tietze, D. ; Chaudret, B. (2008)
Mechanisms of dipolar ortho/para-H2O conversion in ice.
In: Zeitschrift Fur Physikalische Chemie-International Journal of Research in Physical Chemistry & Chemical Physics, 222 (7)
Artikel, Bibliographie
Dies ist die neueste Version dieses Eintrags.
Kurzbeschreibung (Abstract)
In this paper a possible explanation for an unexpected ortho/para-water ratio in the gas clouds of comets is given. The description is based on the quantum-mechanical density matrix formalism and the spin temperature concept. Only the nuclear spin system is treated quantum-mechanically. Employing the model of a four spin system, created by two nearest neighbour water molecules, spin eigenstates and their dynamics under the influence of their mutual dipolar interactions are studied. It is shown that a fast conversion between ortho- and para-states occurs on a msec time scale, caused by the intermolecular homonuclear magnetic dipolar interaction. Moreover the spin eigenstates of water in an ice crystal are determined by magnetic dipolar interactions and are not given by normal ortho- and para-H2O states of gaseous water. As a result of this the spin temperature of gaseous water evaporated from ice depends strongly on its evaporation history and the ortho/para-ratio of water molecules are only an indirect measure of the temperature of ice crystals from where they descend. This result could explain the unexpected experimentally observed ortho/para-ratios in the clouds of comets.
| Typ des Eintrags: | Artikel |
|---|---|
| Erschienen: | 2008 |
| Autor(en): | Buntkowsky, G. ; Limbach, H. H. ; Walaszek, B. ; Adamczyk, A. ; Xu, Y. ; Breitzke, H. ; Schweitzer, A. ; Gutmann, T. ; Wächtler, M. ; Frydel, J. ; Emmler, T. ; Amadeu, N. ; Tietze, D. ; Chaudret, B. |
| Art des Eintrags: | Bibliographie |
| Titel: | Mechanisms of dipolar ortho/para-H2O conversion in ice |
| Sprache: | Englisch |
| Publikationsjahr: | 2008 |
| Titel der Zeitschrift, Zeitung oder Schriftenreihe: | Zeitschrift Fur Physikalische Chemie-International Journal of Research in Physical Chemistry & Chemical Physics |
| Jahrgang/Volume einer Zeitschrift: | 222 |
| (Heft-)Nummer: | 7 |
| URL / URN: | http://apps.webofknowledge.com/full_record.do?product=WOS&se... |
| Zugehörige Links: | |
| Kurzbeschreibung (Abstract): | In this paper a possible explanation for an unexpected ortho/para-water ratio in the gas clouds of comets is given. The description is based on the quantum-mechanical density matrix formalism and the spin temperature concept. Only the nuclear spin system is treated quantum-mechanically. Employing the model of a four spin system, created by two nearest neighbour water molecules, spin eigenstates and their dynamics under the influence of their mutual dipolar interactions are studied. It is shown that a fast conversion between ortho- and para-states occurs on a msec time scale, caused by the intermolecular homonuclear magnetic dipolar interaction. Moreover the spin eigenstates of water in an ice crystal are determined by magnetic dipolar interactions and are not given by normal ortho- and para-H2O states of gaseous water. As a result of this the spin temperature of gaseous water evaporated from ice depends strongly on its evaporation history and the ortho/para-ratio of water molecules are only an indirect measure of the temperature of ice crystals from where they descend. This result could explain the unexpected experimentally observed ortho/para-ratios in the clouds of comets. |
| Freie Schlagworte: | ortho para-water spin temperature dipolar interaction comets ice parahydrogen-induced polarization transition-metal dihydrides situ phip-nmr homogeneous hydrogenation stereoselective hydrogenation magnetic-resonance spin polarization comet p/halley water masers complexes |
| Zusätzliche Informationen: | 353IF Times Cited:23 Cited References Count:52 |
| Fachbereich(e)/-gebiet(e): | 07 Fachbereich Chemie 07 Fachbereich Chemie > Eduard Zintl-Institut 07 Fachbereich Chemie > Eduard Zintl-Institut > Fachgebiet Physikalische Chemie |
| Hinterlegungsdatum: | 27 Okt 2014 20:37 |
| Letzte Änderung: | 03 Jul 2024 02:22 |
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| Suche nach Titel in: | TUfind oder in Google |
Verfügbare Versionen dieses Eintrags
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Mechanisms of Dipolar Ortho/Para-H2O Conversion in Ice. (deposited 01 Okt 2021 11:32)
- Mechanisms of dipolar ortho/para-H2O conversion in ice. (deposited 27 Okt 2014 20:37) [Gegenwärtig angezeigt]
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