Gaseous protonated nitrosamide. A G2 theoretical study on the structure, stability, and interconversion of (H2NNO) H+ isomers

The (H2NNO)H+ potential energy surface has been investigated at the G2 level of theory. The ion-dipole adduct H3NNO+ 1 is the most stable protomer, and the proton affinity of H2NNO is computed as 191.3 kcal mol−1. The H2NNOH+ ion 2 and H2NNHO+ ion 3 are less stable than 1 by 2 and 13 kcal mol−1, respectively. All the isomers lie into deep potential wells, and should be in principle observed as distinguishable species in the gas phase. Our theoretical data are used to discuss the conceivable structure of the gaseous protonated nitrosamide recently observed by Egsgaard et al.