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

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. Tables 3, 6, and 10 are available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/543/A46