Structures and stabilities of asymmetrical dimer radical cation systems (AH3–H2O)+ (A=N, P, As)

Abstract

Structures, stabilities, binding energies, and bonding nature of the dimer radical cation systems (AH3–H2O)+ (A=N, P, As) have been studied using B3LYP, MP2, and CCSD methods. The local minima of (NH3–H2O)+ include a hemi-bonded structure (H3N+···OH2), a proton-transferred hydrogen-bonded structure (H3NH+···OH), and a non-proton-transferred hydrogen-bonded structure (H2N–H+···OH2) which is the most stable conformer. Both the P and As complexes have four local minima. In addition to the three structures found for the nitrogen analog, a second proton-transferred hydrogen-bonded structure (H2A···H–OH2 +) was found. For the P complexes, the hemi-bonded structure (H3P+···OH2) is the most stable complex, while for the As compounds the hemi-bonded structure (H3As+···OH2) and hydrogen-bonded structure (H2As···H–OH2 +) are the most stable ones. The atomic spin density and charge population and properties at the bond critical points have been calculated to study the structures and bonding characters of these dimer radical cations.