Anharmonic rotational and vibrational spectroscopic constants of NH2CH2OH

Abstract

The recent experimental identification of aminomethanol (NH₂CH₂OH) and its synthesis under simulated interstellar conditions suggests that it may be formed, and thus observable, in the interstellar medium. To aid in its possible detection, this work presents high-level theoretical, anharmonic vibrational and rotational spectroscopic data for the three lowest-energy conformers of NH₂CH₂OH. All three conformers fall within 0.80 kcal mol⁻¹ of each other at the CCSD(T)-F12b/cc-pCVTZ-F12 level, with an anharmonic zero-point vibrational energy correction. Additionally, all three conformers are shown to have multiple vibrational frequencies with intensities greater than 100 km mol⁻¹. The most notable of these are the symmetric O-C-N stretch of the lower-energy C₁ conformer at 976.4 cm⁻¹, the C-O stretch of the C_s conformer at 964.9 cm⁻¹, and the antisymmetric O-C-N stretch of the higher-energy C₁ conformer at 1099.0 cm⁻¹. While much of the vibrational spectra of the three overlap, these features should help to separate them. Finally, all three conformers have non-zero dipole moments on the order of 1 D, suggesting that they may be observable by rotational spectroscopy, as well. In all cases, the computational data provided herein will help to facilitate future experimental and observational studies on this key molecule in the formation of extraterrestrial amino acids.