Description: Rotational Tunneling in CH4 II: disorder effects

This title appears in the Scientific Report : 2011

Rotational Tunneling in CH4 II: disorder effects

Transitions within the tunneling multiplet of CH(4) in phase II have been measured in an experiment at the backscattering instrument BASIS of the Neutron Source SNS. They all involve transitions from or to T-states. A statistical model is put forward which accounts for local departures from tetrahed...

Personal Name(s):	Press, W.
	Krasnow, I. / Zamponi, M. / Prager, M.
Contributing Institute:	Neutronenstreuung; ICS-1 Streumethoden; JCNS-2 Neutronenstreuung; JCNS-1 JCNS-FRM-II; JCNS-FRM-II
Published in:	The @journal of chemical physics, 135 (2011) S. 224509
Imprint:	Melville, NY American Institute of Physics 2011
Physical Description:	224509
PubMed ID:	22168705
DOI:	10.1063/1.3664726
Document Type:	Journal Article
Research Program:	Großgeräte für die Forschung mit Photonen, Neutronen und Ionen (PNI) BioSoft: Makromolekulare Systeme und biologische Informationsverarbeitung
Series Title:	Journal of Chemical Physics 135
Subject (ZB):	J Chemistry > 0 Basic research > 1 Others > 0
Link:	Get full text Published under German "Allianz" Licensing conditions on 2011-12-12. Available in OpenAccess from 2011-12-12
	Publikationsportal JuSER

Please use the identifier: http://hdl.handle.net/2128/7370 in citations.
Please use the identifier: http://dx.doi.org/10.1063/1.3664726 in citations.

Transitions within the tunneling multiplet of CH(4) in phase II have been measured in an experiment at the backscattering instrument BASIS of the Neutron Source SNS. They all involve transitions from or to T-states. A statistical model is put forward which accounts for local departures from tetrahedral symmetry at the sites of ordered molecules. Different from previous work, in which discrete sets of overlap matrix elements have been studied, now large numbers of elements as well as the ensemble of T-states are considered. The observed neutron spectra can be explained rather well, all based on the pocket state formalism of A. Hüller [Phys. Rev. B 16, 1844 (1977)]. A completely new result is the observation and simulation of transitions between T-states, which give rise to a double peaked feature close to the elastic position and which reflect the disorder in the system. CH(2)D(2) molecules in the CH(4) matrix are largely responsible for the disorder and an interesting topic for their own sake. The simple model presented may lend itself to a broader application.