Possible Interstellar Formation Routes of PN from PH3 + N(4S) & NH2 + P(4S) and Spectroscopic Characterization of the Intermediates Including HNPH

Abstract

While the known interstellar molecule PN could be formed from reactions of atoms with diatomic hydrides, this work shows that PN may also be formed from reactions of phosphine or ${\tilde{X}}^2{B}_1$ NH₂ with nitrogen or phosphorus atoms, respectively. All of these species are known in the interstellar medium (ISM), and their reactions provide for means of producing PN by way of HNP/HPN and ³A HPNH. This work also shows that ${\tilde{X}}^2{B}_1$ PH₂ can arise from reactions of phosphine with atomic nitrogen under warm conditions. Additionally, the fundamental vibrational frequencies and spectroscopic constants for five of the intermediates in these reactions are provided: ¹A′ trans-HNPH, ¹A′ cis-HNPH, ³A HPNH, ³A″ PNH₂, and ³A″ NPH₂. Observation of any of these molecules, whether in the laboratory, or in the ISM could imply that reaction of PH₃/PH₂ or NH₂ with the right atoms could produce PN and possibly kickstart phosphorus’s role in prebiotic chemistry.