Lifetime Measurement of d³Π_u State of Hydrogen Molecule

Abstract

Radiative lifetimes of H₂(d³Π_u) in single rovibronic levels were measured by means of a delayed coincidence method combined with pulsed-electron impact excitation. The observed emission lines were selected Q- and R-rotational lines of the d³Π_u→a³Σ_g⁺ transition. It was found that the lifetimes of Π⁻-sublevels of v=0, 1, 2, 3, K=2 levels and of v=0, K=1 level were about 40 ns independent of rovibronic level, while the lifetimes of Π⁺-sublevels were strongly dependent on the vibrational level. The anomaly of the lifetimes of Π⁺-sublevels could be explained by an interaction between the d³Π_u- and the e³ Σ_u⁺-levels.