Title: Relevance of the P+O2 Reaction for PO Formation in Astrochemical Environments: Electronic Structure Calculations and Kinetic Simulations
Authors: Juan García de la Concepción, Carlo Cavallotti, Vincenzo Barone, Cristina Puzzarini, Izaskun Jiménez-Serra
DOI: https://doi.org/10.3847/1538-4357/ad1ffa
Date: 10/03/2024
Working Group: WG5
Grant Period: 2
Grant Period Goal (number): GAPG-1, GAGP-7
Covered deliverables from the MoU (number): 5.5.3, 5.6.3
Countries involved: Italy, Spain
Number of female/young/ITC coauthors: 3
Abstract: Phosphorus monoxide (PO) is a key brick of prebiotic chemistry since it is a potential precursor of phosphates, which are present in all living systems. Prompted by the lack of information on the different processes involved in the formation of PO, we have revisited and analyzed in detail the P(4S) + O2(3Σ−) and P(4S) + O2(1Δ) reactions leading to PO. The former process has been widely studied from both experimental and theoretical points of view, however, with contradictory results. We have used high-level quantum-chemical calculations to accurately describe the reaction mechanisms. Next, rate constants have been computed using a master equation approach based on ab initio transition state theory. By incorporating the P(4S) + O2(3Σ−) reaction in an astrochemical model, we have found that this reaction cannot be overlooked when aiming at a complete understanding of the PO abundance in regions dominated by shocks with speeds below 40 km s−1.
