Methyl quantum tunneling in ionic liquid [DMIm][TFSI] facilitated by Bis(trifluoromethane)sulfonimide lithium salt.
Sci Rep
; 8(1): 10354, 2018 Jul 09.
Article
en En
| MEDLINE
| ID: mdl-29985444
ABSTRACT
We probe, for the first time, quantum tunneling in the methyl groups of the ionic liquid [DMIm][TFSI] facilitated by the presence of Bis(trifluoromethane)sulfonimide lithium salt. The observation of tunneling is made possible by crystallization, rather than vitrification, of [DMIm][TFSI] at low temperature. Neutron scattering measurements detect quantum tunneling excitations at ~27 µeV at temperatures below 30 K in the presence of LiTFSI at a concentration of 1 mol/kg, but not in salt-free [DMIm][TFSI]. This indicates that the methyl rotational potential barrier is reduced by the presence of LiTFSI, thus bringing the tunneling excitations into the measurable range. The salt-induced reduction of the rotational barrier is corroborated by quasi-elastic scattering data associated with stochastic re-orientation of methyl groups measured between 40 and 60 K.
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1
Colección:
01-internacional
Base de datos:
MEDLINE
Idioma:
En
Revista:
Sci Rep
Año:
2018
Tipo del documento:
Article
País de afiliación:
Estados Unidos