Large prebiotic molecules in space: photo-physics of acetic acid and its isomers

TL;DR

This paper investigates the photo-physics of acetic acid and its isomers in space, computing their electronic and vibrational properties to understand their behavior under solar radiation, with implications for prebiotic chemistry.

Contribution

It provides detailed density functional theory calculations of acetic acid and isomers, and analyzes their space-based photo-absorption characteristics and emission regions.

Findings

Computed photo-absorption rates agree with previous estimates.

Glycolaldehyde emission is diffuse in Sgr B2(N), unlike other isomers.

Acetic acid and methyl formate emissions are concentrated in a compact region.

Abstract

An increasing number of large molecules have been positively identified in space. Many of these molecules are of biological interest and thus provide insight into prebiotic organic chemistry in the protoplanetary nebula. Among these molecules, acetic acid is of particular importance due to its structural proximity to glycine, the simplest amino acid. We compute electronic and vibrational properties of acetic acid and its isomers, methyl formate and glycolaldehyde, using density functional theory. From computed photo-absorption cross-sections, we obtain the corresponding photo-absorption rates for solar radiation at 1 AU and find them in good agreement with previous estimates. We also discuss glycolaldehyde diffuse emission in Sgr B2(N), as opposite to emissions from methyl formate and acetic acid that appear to be concentrate in the compact region Sgr B2(N-LMH).