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Helium Tagging of Protonated Methane in Messenger Spectroscopy: Does It Interfere with the Fluxionality of CH 5 + ?
Author(s) -
Uhl Felix,
Marx Dominik
Publication year - 2018
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201808531
Subject(s) - intermolecular force , chemistry , intramolecular force , scrambling , protonation , spectroscopy , molecule , physics , stereochemistry , ion , linguistics , philosophy , organic chemistry , quantum mechanics
Messenger infrared predissociation spectroscopy is an powerful technique to investigate elusive molecules. Despite accumulating evidence that 4 He‐tagging has a minor effect on structure due to its weak interactions, its impact on intramolecular large‐amplitude motion is much less clear. Using one of the most floppy molecules known, protonated methane, we investigate to what extent helium tags perturb its salient fluxionality, underlying full hydrogen scrambling. Bosonic path integral quantum simulations show that the impact of attaching up to four 4 He messengers to CH 5 + is negligible compared to the non‐tagged bare species. This non‐invasive nature is unrelated to the bosonic character of 4 He. Yet, hydrogen scrambling has a pronounced effect on the microsolvation shell pattern of CH 5 + ⋅He n that emerges as a result of tagging. These findings should provide impetus to explore the power of He‐tagging, particularly in the realm of weakly bound intermolecular complexes.