In search of phosphorus in astronomical environments: The reaction between the CP radical (X²Σ⁺) and methanimine

Phosphorus is of particular interest in astrochemistry because it is a biogenic element together with hydrogen, carbon, nitrogen, oxygen, and sulfur. However, the chemical evolution of such element in the interstellar medium (ISM) is still far from an accurate characterization, with the chemistry of P-bearing molecules being poorly understood. To provide a contribution in this direction, we have carried out an accurate investigation of the potential energy surface for the reaction between the CP radical and methanimine (CH₂NH), two species already detected in the ISM. In analogy to similar systems, i.e., CH₂NH + X, with X = OH, CN, and CCH, this reaction can occur-from an energetic point of view-under the harsh conditions of the ISM. Furthermore, since the major products of the aforementioned reaction, namely, E- and Z-2-phosphanylidyneethan-1-imine (HN=CHCP) and N-(phosphaneylidynemethyl)methanimine (H₂C=NCP), have not been spectroscopically characterized yet, some effort has been made for filling this gap by means of accurate computational approaches.