The N₄ molecule and the N₃⁺ ion

Abstract

The possibility of the nitrogen molecule forming a stable dimer is investigated. Through ab initio calculations in an extended contracted-gaussian basis, it is demonstrated that N₄ in tetrahedral geometry and N₃ ⁺ in D _3h geometry are local minimum points on their respective internuclear potential energy surfaces. The N₄ molecule is considerably higher in energy than two ground-state N₂ molecules and some study of the barrier for N₄ decomposition has been made. The bond lengths and force constants for the two systems are shown to be similar to their hydrocarbon counterparts, C₄H₄ and C₃H₃ ⁺, tetrahedrane and cyclopropenyl cation. Other related systems are discussed as well.