Title: High-resolution ro-vibrational and rotational spectroscopy of deuteronated formaldehyde, H2COD+
Authors: Denis Comte; Mattia Melosso; Hunarpreet Kaur; Ernest A. Michael; Terri E. Field-Theodore; Weslley G. D. P. Silva; Dennis F. Dinu; Silvia Alessandrini; Luca Bizzocchi; Sandra Brünken; Cristina Puzzarini; Stephan Schlemmer; Oskar Asvany
DOI: 10.1039/d6cp02136k
Date: 2026-08-04
Working Group: WG5
Grant Period: 4
Grant Period Goal (number): 8
Covered deliverables from the MoU (number): 5.7.3.; 1.3.2.; 1.4.2.
Countries involved: Italy; Germany; Netherlands
Number of female/young/ITC coauthors: 9
Is the publication open access?: No
Is the publication co-lead by a YRI?: Yes
Abstract: Among the deuterated forms of protonated formaldehyde, astrochemical models predict H2COD+ as the most abundant isotopologue in prestellar cores. However, its observation is currently hampered by the lack of high-resolution molecular data. In this work, both the ro-vibrational and rotational spectra of H2COD+ were investigated in a 4 K cryogenic ion trap instrument employing the leak-out spectroscopy method. Ro-vibrational transitions associated with the ν1 fundamental band (antisymmetric C–H stretching) were detected in the region between 3095 and 3155 cm−1 and assigned with the support of high-level quantum-chemical calculations. Preliminary analysis of the ro-vibrational lines enabled us to predict the rotational spectrum of the ground vibrational state with high accuracy. Subsequently, 36 pure rotational transitions were measured using a rotational-vibrational double-resonance scheme. The simultaneous analysis of both ro-vibrational and rotational data yielded highly accurate ground state spectroscopic parameters that can be used for future radio astronomical searches of H2COD+ in the interstellar medium. Finally, these ground state rotational constants, together with those of three additional isotopologues, were employed to derive an almost complete semi-experimental equilibrium structure for protonated formaldehyde.
