Work

Assignment of collision-induced four-level double-resonance transitions in the 3ν3 ← ν3 spectral region of methane

Year: 2025

Type: article

Abstract: Optical-optical double-resonance (OODR) spectroscopy using a narrow-linewidth pump and a frequency comb probe has previously been used to measure and assign sub-Doppler transitions in the 3ν3 ← ν3 spectral region [Hjältén et al., J. Chem. Phys. 161, 124311 (2024)] when pumping from the J = (7, A2) ground state. Doppler-broadened double-resonance transitions were also observed in those OODR spectra. In this paper, 68 of these Doppler-broadened transitions are assigned to four-level double-resonance transitions involving collisional transfer from the pumped A1 symmetry state to other A1 and A2 symmetry (I = 2 meta nuclear spin) levels of the ν3 fundamental state. Assignments are made using combination differences and comparison with the term values and intensities of lines predicted by a new effective Hamiltonian, the accuracy of which has been validated by the sub-Doppler transitions. No collisional OODR transitions were observed to known final states starting from states in the ν1 fundamental band, nor from other symmetries of the ν3 fundamental band.

Source: The Journal of Chemical Physics

DOI: 10.1063/5.0285618

Authors: Kevin K. Lehmann, Adrian Hjältén, Isak Silander, Michael Rey, Aleksandra Foltynowicz

Institutions: University of Virginia, Umeå University, Centre National de la Recherche Scientifique, Groupe de Spectrométrie Moléculaire et Atmosphérique

Language: English

Topic: Spectroscopy and Laser Applications

Subfield: Spectroscopy

Field: Chemistry

Domain: Physical Sciences

Open Access status: hybrid

Estimated APC paid: $3,500