The submillimeter-wave spectrum of the doubly deuterated species of methyl formate HCOOCD₂H^⋆

L. H. Coudert¹, L. Margulès², T. R. Huet², R. A. Motiyenko², H. Møllendal³ and J.-C. Guillemin⁴

¹ LISA, UMR 7583 CNRS – Universités Paris Est Créteil et Paris Diderot, 61 avenue du Général de Gaulle, 94010 Créteil, France
e-mail: laurent.coudert@lisa.u-pec.fr
² Laboratoire de Physique des Lasers, Atomes et Molécules, UMR 8523 CNRS – Université Lille I, Bât. P5, 59655 Villeneuve d’ Ascq Cedex, France
³ Centre for Theoretical and Computational Chemistry (CTCC), Department of Chemistry, University of Oslo, PO Box 1033 Blindern, 0315 Oslo, Norway
⁴ Sciences Chimiques de Rennes, UMR 6226 CNRS – ENSCR, Avenue du Général Leclerc, CS 50837, 35708 Rennes Cedex 7, France

Received: 27 February 2012
Accepted: 17 April 2012

Abstract

Context. Astronomical surveys of interstellar molecules, such as those that will be available with the very sensitive ALMA telescope, require preliminary laboratory investigations of the microwave and submillimeter-wave spectra of new molecular species to identify these in the interstellar media.

Aims. We build a linelist that should allow us to detect HCOOCD₂H, provided it is present in the interstellar media in a suitable concentration.

Methods. The experimental spectra of HCOOCD₂H have been recorded in the microwave and submillimeter-wave energy range. Line frequencies were analyzed using an internal axis method-like treatment taking into account the CD₂H internal rotation.

Results. 5933 lines of HCOOCD₂H have been assigned and their frequencies were reproduced with a unitless standard deviation^⋆⋆ of 1.6. A linelist with calculated frequencies and intensities was built and spans the 50 − 660 GHz spectral region. The frequency accuracy is better than 0.1 MHz.

Conclusions. The pure rotation spectrum of the CD₂H-methyl formate isotopolog (HCOOCD₂H) has been observed in laboratory for the first time.