Metastable Hydrogen Molecules. II. Fine Structure of Parahydrogen

The fine structure of the $N=2$ rotational level of the (1σg, 1πᵤ)c³πᵤ state of parahydrogen, very probably in the $v=0$ vibrational level, has been measured directly by means of the molecular beam magnetic resonance method. The zero field intervals are: f(J=2↔J=1)=4928.003±0.010 Mc/sec, f(J=3↔J=2)=5898.105±0.012 Mc/sec. The spin-spin and spin-orbit interaction constants are in agreement with theoretical predictions based on a simplified hydrogenic model.