Theoretical and experimental research on excimer like (N2)2 dimer: potential energy curves and spectra

Theoretical ab initio calculations for a number of symmetry groups of (N2)2 dimer are performed with an emphasis on the intermolecular distance 1.2⩽R⩽2.5 Å. Except for the D2h group, the ground and excited state potential energy curves of most of the symmetry groups are repulsive in this region. The theoretical results indicated that there exists an excimer like electric dipole transition between the excited singlet states a1B2g and a1B3u of the D2h symmetry group. The oscillator strength and theoretical spectra are calculated. Experimentally observed emission spectra for the excimer-like (N2)2 dimer is found to be in good agreement with our theoretical calculations.