MOLECULAR-BEAM MEASUREMENTS OF EMISSION SPECTRUM AND RADIATIVE LIFETIME OF N2 IN METASTABLE EPSILON3SIGMAG+ STATE

Electron-impact excitation of a molecular beam of nitrogen was used to produce the metastable E 3∑g+ state. This state, which lies 11.87 eV above the ground state, has recently been observed in a number of electron-impact experiments. This paper reports the emission spectrum from the molecular beam, and identifies three forbidden electronic transitions, E 3∑g+ → A 3∑g+, E3∑g +→B3∏g and E3∑ g+→C3∏u. Approximate absolute transition probabilities are determined. The radiative lifetime of the E state is 270± 100 psec, and the equilibrium internuclear distance is 1.16±0.02 Å.