Fine structure and hyperfine structure of ortho-H2 d(3p) 3Πu (v=0–3) via microwave optical magnetic resonance induced by electrons

Abstract

Microwave Optical Magnetic Resonance Induced by Electrons (MOMRIE) has been observed for vibrational levels v = 0–3 of ortho‐H₂ in the ${\text{d(3p)\hspace{0.17em}}}^3{\Pi }_u$ state with rotational quantum number N = 1. The theory used to analyze the spectrum is essentially the same as that which has previously been applied to the metastable ${\text{c(2p)\hspace{0.17em}}}^3{\Pi }_u$ state, but several additions are also given. The theory, as previously, has been formulated in terms of a representation in which the angular momenta are all coupled. However, a semi‐quantitative formulation in terms of an entirely decoupled representation (which is more nearly appropriate for the MOMRIE experiment) is also presented. Least squares fits of the observed MOMRIE lines to the coupled theory provide accurate determinations of the fine and hyperfine structure parameters. Parameters determined in this way include those commonly referred to as the spin‐orbit coupling constant, the spin‐spin coupling constant, the dipolar hyperfine coupling constant, the orbital angular momentum hyperfine parameter, and the orbital angular momentum g factor. Vibrational variation of the fine structure parameters is easily measurable while that of the hyperfine structure parameters is comparable to the experimental error. The linewidth of the MOMRIE transitions yields a lifetime of 32±5 nsec for the state.