Knowledge Bank

Electron impact excitation of a molecular beam of nitrogen was used to produce the metastable $E3\Sigma g+$ state. This state, which lies 11.87 eV above the ground state, has recently been observed in a number of electron impact experiments. This talk reports the emission spectrum from the molecular beam, and identifies three forbidden electronic transitions, $E3\Sigma g+\to A3\Sigma u+,E3\Sigma g+\to B2\Pi g$ and $E3\Sigma g\to C3\Pi u$. Approximate absolute transition probabilities are determined. The radiative lifetime of the E state is $270\pm 100\mu$sec, and the equilibrium internuclear distance is $1.16\pm 0.02\backslash AA$.