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Titolo:
Reorientational motion of the HS- ions in hydrogensulfides of alkali metals (NaHS, KHS, RbHS): A quasielastic neutron scattering study
Autore:
Haarmann, F; Jacobs, H; Asmussen, B; Noldeke, C; Kearley, GJ; Combet, J;
Indirizzi:
Univ Dortmund, Fachbereich Chem, D-44221 Dortmund, Germany Univ Dortmund Dortmund Germany D-44221 h Chem, D-44221 Dortmund, Germany Interfac Reactor Inst, NL-2629 JB Delft, Netherlands Interfac Reactor Inst Delft Netherlands NL-2629 JB JB Delft, Netherlands Univ Kiel, Inst Expt & Angew Phys, D-24098 Kiel, Germany Univ Kiel Kiel Germany D-24098 Expt & Angew Phys, D-24098 Kiel, Germany Inst Max Von Laue Paul Langevin, F-38042 Grenoble, France Inst Max Von Laue Paul Langevin Grenoble France F-38042 Grenoble, France
Titolo Testata:
JOURNAL OF CHEMICAL PHYSICS
fascicolo: 18, volume: 113, anno: 2000,
pagine: 8161 - 8167
SICI:
0021-9606(20001108)113:18<8161:RMOTHI>2.0.ZU;2-E
Fonte:
ISI
Lingua:
ENG
Soggetto:
AMIDE IONS; ROTATIONAL-DYNAMICS; PHASE-TRANSITIONS; ORIENTATIONAL ORDER; ISOTYPIC PHASES; CALCIUM AMIDE; DIFFRACTION; SODIUM; DEUTERIUM; POTASSIUM;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
30
Recensione:
Indirizzi per estratti:
Indirizzo: Haarmann, F Univ Dortmund, Fachbereich Chem, AC 1, D-44221 Dortmund, Germany Univ Dortmund AC 1 Dortmund Germany D-44221 Dortmund, Germany
Citazione:
F. Haarmann et al., "Reorientational motion of the HS- ions in hydrogensulfides of alkali metals (NaHS, KHS, RbHS): A quasielastic neutron scattering study", J CHEM PHYS, 113(18), 2000, pp. 8161-8167

Abstract

The isostructural hydrogensulfides of the alkali metals sodium, potassium,and rubidium were investigated by quasielastic neutron scattering in orderto gain insight into the dynamics of the molecular anion HS- as a functionof temperature. A phase transition between the rhombohedral middle temperature modification (MTM) and the cubic high temperature modification (HTM) of the title compounds was of special interest. A two site jump model is clearly supported by the data of the MTM and an eight site jump model is consistent with the data of the HTM. The jump distances are in reasonable agreement with distances of the hydrogen positions determined by neutron powder diffraction on the fully deuterated samples. At the MTM --> HTM phase transition the correlation times of the reorientational motion decrease by about one order of magnitude. Within the investigated temperature range (T=170 K to T=450 K) they change from 10(-8) s to 10(-12) s. They show Arrhenius behavior. The activation enthalpies of the MTM decrease with increasing radiusof the cation from 26(1) kJ mol(-1), 22(1) kJ mol(-1) to 18(2) kJ mol(-1) for NaHS, KHS and RbHS respectively. In the HTM they are equal within the estimated error 6(1) kJ mol(-1) and 7(1) kJ mol(-1) for NaHS and KHS. (C) 2000 American Institute of Physics. [S0021-9606(00)52941-9].

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Documento generato il 25/09/20 alle ore 12:24:20