Rovibrational spectroscopy of the CH${}^{+}$-He and CH${}^{+}$-He${}_4$ complexes

Abstract

A cryogenic 22-pole ion trap apparatus is used in combination with a table-top pulsed IR source to probe weakly bound CH${}^{+}$-He and CH${}^{+}$-He${}_4$ complexes by predissociation spectroscopy at 4 K. The infrared photodissociation spectra of the C-H stretching vibrations are recorded in the range of 2720-2800 cm${}^{-1}$. The spectrum of CH${}^{+}$-He exhibits perpendicular transitions of a near prolate top with a band origin at 2745.9 cm${}^{-1}$, and thus confirms it to have a T-shaped structure. For CH${}^{+}$-He${}_4$, the C-H stretch along the symmetry axis of this oblate top results in parallel transitions.

arXiv comment6 pages, 2 Tables, 5 Figures Accepted for publication in the Journal of Molecular Spectroscopy 14 January 2021

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