Rovibronic spectroscopy of PN from first principles.

Mikhail Semenov,Sergei N Yurchenko,Jonathan Tennyson,Nayla El-Kork

doi:10.1039/d1cp02537f

Abstract

We report an ab initio study on the rovibronic spectroscopy of the closed-shell diatomic molecule phosphorous mononitride, PN. The study considers the nine lowest electronic states, X 1Σ+, A 1Π, C 1Σ−, D 1Δ, E 1Σ−, a 3Σ+, b 3Π, d 3Δ and e 3Σ− using high level electronic structure theory and accurate nuclear motion calculations. The ab initio data cover 9 potential energy, 14 spin–orbit coupling, 7 electronic angular momentum coupling, 9 electric dipole moment and 8 transition dipole moment curves. The Duo nuclear motion program is used to solve the coupled nuclear motion Schrödinger equations for these nine electronic states and to simulate rovibronic absorption spectra of 31P14N for different temperatures, which are compared to available spectroscopic studies. Lifetimes for all states are calculated and compared to previous results from the literature. The calculated lifetime of the A1Π state shows good agreement with an experimental value from the literature, which is an important quality indicator for the ab initio A–X transition dipole moment.

Highlights

Phosphorus is considered to be one of the key elements as a source of life and replication on our planet,[1,2] with PN being one of the candidates in star and meteorite evolution to provide the necessary life building material
We report an ab initio study on the rovibronic spectroscopy of the closed-shell diatomic molecule phosphorous mononitride, PN
In this work we present a comprehensive ab initio spectroscopic model for the nine lowest electronic states of phosphorous mononitride, X 1S+, A 1P, C 1SÀ, D 1D, E 1S+, a 3S+, b 3P, d 3D, e 3SÀ, consisting of potential energy curves (PECs), transition dipole moments curves (TDMCs), spin–orbit coupling curves (SOCs) and angular momentum coupling curves (AMCs) using

Summary

Introduction

Phosphorus is considered to be one of the key elements as a source of life and replication on our planet,[1,2] with PN being one of the candidates in star and meteorite evolution to provide the necessary life building material. There have been multiple observations of PN in different media in space: hot dense molecular clouds,[3,4] energetic star forming regions,[5,6] cold cloud cores,[5,7] red giant stars[8,9,10] and protoplanetary nebula.[8] Regardless of high astrophysical and astrobilogical importance, phosphorous mononitride is one of the experimentally least-well studied diatomic molecules of its isoelectronic group (P2, SiO, N2, CS). Most of the high resolution spectroscopy experiments with PN concentrated on the electronic system A 1P–X 1S+,11,13,19–21 with E 1S+–X 1S+ being confirmed afterwards,[22,23,24] and several valence and Rydberg states have been studied as well.[25,26]

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