Radiative decay constants of the H2 Fulcher bands

Abstract
The radiative decay constants corresponding to the Fulcher bands of the H2 molecular spectrum are obtained using pulsed‐electron beam techniques. Data in the range ∼1.8 to 2.8×107 s−1 are obtained at 25 eV incident electron energy for the d 3πua 3Σ+g (v′, v) Q (K) and k 3πua 3Σ+g (v′,v) Q (K) rotational lines with K=1,2,3 and v′=0,1,2,3,→v=0,1,2,3. Additional measurements of the d 3πua 3Σg+(0,0) Q1 rotational line intensity indicate the presence of a two‐mode decay over the energy range 50–300 eV. The long‐lived decay component, identified as radiative cascade from upper levels, contributes ∼15% to the total d 3πu(v′=0) population.