Computational Infrared Spectroscopy of 958 Phosphorus-bearing Molecules

TL;DR

This paper introduces a computational approach to generate infrared spectra for 958 phosphorus-bearing molecules, aiding astrochemical detection efforts and expanding spectral databases for future research.

Contribution

It presents a high-throughput quantum chemistry method to produce a large spectral database for phosphorus molecules, enhancing existing data and supporting astrochemical applications.

Findings

Generated spectra for 958 P-molecules using computational methods

Provided data useful for identifying spectral ambiguities in astronomy

Highlighted limitations in spectral accuracy for experimental detection

Abstract

Phosphine is now well established as a biosignature, which has risen to prominence with its recent tentative detection on Venus. To follow up this discovery and related future exoplanet biosignature detections, it is important to spectroscopically detect the presence of phosphorus-bearing atmospheric molecules that could be involved in the chemical networks producing, destroying or reacting with phosphine. We start by enumerating phosphorus-bearing molecules (P-molecules) that could potentially be detected spectroscopically in planetary atmospheres and collecting all available spectral data. Gaseous P-molecules are rare, with speciation information scarce. Very few molecules have high accuracy spectral data from experiment or theory; instead, the best available data is from the RASCALL approach and obtained using functional group theory. Here, we present a high-throughput approach utilising established computational quantum chemistry methods (CQC) to produce a database of approximate infrared spectra for 958 P-molecules. These data are of interest for astronomy and astrochemistry (importantly identifying potential ambiguities in molecular assignments), improving RASCALL's underlying data, big data spectral analysis and future machine learning applications. However, this data will probably not be sufficiently accurate for secure experimental detections of specific molecules within complex gaseous mixtures in laboratory or astronomy settings.