Related Experiment Video
Updated: Jun 5, 2025

Coulomb Explosion Imaging as a Tool to Distinguish Between Stereoisomers
Published on: August 18, 2017
Helium Nanodroplet Infrared Spectroscopic Studies of CH4+ and 13CH3
Amandeep Singh1, Sofia H Allison1,2, Andrew Abhisek A Azhagesan1,3
1Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States.
Abstract:
In this work, CH4+ cations were formed in helium droplets and investigated with infrared laser spectroscopy. The observed infrared bands are assigned to the C2v isomer of the CH4+ cation. The rotational structure of the bands remains unresolved, indicating a factor of 3 or larger decrease in the rotational constants in helium nanodroplets. We also report on the observation of the spectrum of isotopically substituted 13CH3+ cations in He droplets, which shows a well-resolved rotational structure. The rotational constant A for rotation about the C3 axis of CH3+ in helium was found to be a factor of 1.17 smaller than in the gas phase.
Related Concept Videos
Inductive Effects on Chemical Shift: Overview
Mass Spectrum: Interpretation
To...
Carbon-13 (¹³C) NMR: Overview
¹³C NMR: ¹H–¹³C Decoupling
A broadband decoupling technique is used to simplify these complex, sometimes overlapping, signals. Broadband decoupling relies on a...
¹³C NMR: Distortionless Enhancement by Polarization Transfer (DEPT)
Mass Spectrometry: Alkyl Halide Fragmentation

