Laboratory spectroscopy of 1,2-propanediol at millimeter and submillimeter wavelengths

TL;DR

This study provides detailed spectroscopic data for 1,2-propanediol, aiding its detection in space by radio telescopes, which is crucial for understanding complex organic molecules in molecular clouds.

Contribution

The paper presents extensive rotational spectra and spectroscopic parameters of 1,2-propanediol up to eighth order, facilitating future astronomical searches for this molecule.

Findings

Spectroscopic parameters for 1,2-propanediol established up to eighth order.

Data covers 38 to 400 GHz frequency range.

Results will help detect 1,2-propanediol in space with ALMA and other telescopes.

Abstract

Ethanediol is one of the largest complex organic molecules detected in space thus far. It has been found in different types of molecular clouds. The two propanediol isomers are the next larger diols. Hence, they are viable candidates to be searched for in space. We wish to provide sufficiently large and accurate sets of spectroscopic parameters of 1,2-propanediol to facilitate searches for this molecule at millimeter and longer submillimeter wavelengths. We recorded rotational spectra of 1,2-propanediol in three wide frequency windows between 38 and 400~GHz. We made extensive assignments for the three lowest energy conformers to yield spectroscopic parameters up to eighth order of angular momentum. Our present data will be helpful for identifying 1,2-propanediol at moderate submillimeter or longer wavelengths with radio telescope arrays such as ALMA, NOEMA, or EVLA. In particular, its detection with ALMA in sources, in which ethanediol was detected, appears to be promising.