[en] The optical emission of N2+(B2Σ+sub(u)→X2Σ+sub(g)) induced by energy transfer (Penning ionization) to nitrogen from 23S metastable helium atoms (He*) has been measured by pulse radiolysis of helium-nitrogen mixtures. The emission decay rate tau-1 varies as a function of helium or nitrogen pressure, which gives a Penning ionization rate constant k2(He*+N2) = (6.8+-0.4)x10-11cm3 molecule-1s-1. (Auth.)