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Toward Detection of FeH⁺ in the Interstellar Medium: Infrared Multiple Photon Dissociation Spectroscopy of Ar₂FeH.

ABSTRACT: The iron hydride molecular cation FeH⁺ is expected to be present in the interstellar medium. Because of the lack of laboratory data, it is yet to be identified in spectrally resolved astronomic observations. As a benchmark for computational predictions and to guide an experimental search for the ro-vibrational lines of FeH⁺, we performed infrared multiple photon dissociation (IRMPD) spectroscopy of FeH⁺ tagged with two argon atoms. The Fe-H stretching mode in Ar₂FeH⁺ is observed at 1860 cm^-1. Combination bands of the Fe-H stretch with the two Fe-H bending and the asymmetric Fe-Ar stretching modes are observed at 2012 cm^-1, 2054 cm^-1, and 2078 cm^-1. Quantum chemical calculations show that the molecule has C_2v symmetry. The Ar-Fe-Ar bending mode at 46 cm^-1 is significantly populated at the temperature of the experiment, causing thermal broadening of the Fe-H stretch and its redshift with increasing internal energy.

SUBMITTER: Jin S

PROVIDER: S-EPMC9251756 | biostudies-literature |

REPOSITORIES: biostudies-literature

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