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Updated: Aug 20, 2026

Characterizing Far-infrared Laser Emissions and the Measurement of Their Frequencies
Published on: December 18, 2015
Near-infrared electronic spectrum of CH2+
Jennifer L Gottfried1, Takeshi Oka
1Department of Chemistry, Department of Astronomy & Astrophysics, the Enrico Fermi Institute, University of Chicago, Chicago, Illinois 60637, USA.
Abstract:
Four vibronic bands of the A 2B1(Piu)<--X 2A1 electronic transition of CH2+ have been observed in the near infrared from approximately 11,000-13,000 cm(-1) using a highly sensitive spectrometer based on a Ti:sapphire laser and a positive column plasma. The two states are derived from the lowest 2Piu state of the linear conformation as a result of a strong Renner-Teller effect. As expected, the rovibronic structure of the CH2+ spectrum is very similar to that of the isoelectronic BH2 radical reported by Herzberg and Johns. Results of a preliminary analysis are given in which the rotational structures of the two states are treated independently, the ground state as a near-prolate asymmetric rotor and the excited state as a linear molecule.
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