Abstract
Ab initio and Perdew, Burke, and Ernzerhof (PBE) density functional theory with dispersion correction (PBE-D3) calculations are performed to study N2Arn (n <= 3) complexes and N-2 trapped in Ar matrix (i.e., N-2@Ar). For cluster computations, we used both Moller-Plesset (MP2) and PBE-D3 methods. For N-2@Ar, we used a periodic-dispersion corrected model for Ar matrix, which consists on a slab of four layers of Ar atoms. We determined the equilibrium structures and binding energies of N-2 interacting with these entities. We also deduced the N-2 vibrational frequency shifts caused by clustering or embedding compared to an isolated N-2 molecule. Upon complexation or embedding, the vibrational frequency of N-2 is slightly shifted, while its equilibrium distance remains unchanged. This is due to the weak interactions between N-2 and Ar within these compounds. Our calculations show the importance of inclusion of dispersion effects for the accurate description of geometrical and spectroscopic parameters of N-2 isolated, in interaction with Ar surfaces, or trapped in Ar matrices.