2021ApJ...915...76S

Herein we present a laboratory rotational study of cyanoacetic acid (CH₂(CN)C(O)OH), an organic acid as well as a -CN-bearing molecule, which is a candidate molecular system to be detected in the interstellar medium (ISM). Our investigation aims to provide direct experimental frequencies of cyanoacetic acid to guide its eventual astronomical search in low-frequency surveys. Using different jet-cooled rotational spectroscopic techniques in the time domain, we have determined a precise set of the relevant rotational spectroscopic constants, including the ¹⁴N nuclear quadrupole coupling constants for the two distinct structures, cis- and gauche-cyanoacetic acid. We believe this work will potentially allow the detection of cyanoacetic acid in the ISM, whose rotational features have remained unknown until now.