REACTION OF P-3) WITH METHYLAMINE - A DETAILED STUDY OF THE POTENTIAL-ENERGY SURFACE AND REACTION-MECHANISMS( (P)

In order to elucidate possible reaction paths to the formation of P-N bonds in interstellar space and to provide data for the interpretation of recent experiments, the reaction of P+ ((3)p) with methylamine has been investigated. In particular, the G2(MP2) methodology has been ap plied to the triplet potential energy surface of [H-5, C, N, P](+). Nu merous minima on this surface have been found, and transition state st ructures connecting those which lie along important reaction paths hav e been determined. The global minimum on the PES is the ion-molecule c omplex P+ NH2CH3, which lies 95.7 kcal/mol below the separated reactan ts. Barrier-free reaction paths leading to (PNH2+ + CH3), (PH + CH2NH2 +), and atomic and molecular hydrogen abstraction have been found. In agreement with experimental results, these first two reactions appear to be favored.