Rotational Moment, Rotational g Factor, Electronic Orbital g Factor, and Anisotropy of the Magnetic Susceptibility of Δ1 O2

The electron paramagnetic resonance spectrum of the Δ1 state of O2 has been investigated in both the J = 2 and J = 3 rotational levels. The line positions in the J = 2 state have been determined to a higher accuracy than previously reported and the J = 3 line positions have been measured for the first time. The combined spectra are analyzed to obtain the rotational constant, rotational g value, electronic orbital g value, and the anisotropy of the magnetic susceptibility of Δ1 O2. From the anisotropy of the susceptibility the electronic second and quadrupole moments are derived. The experimentally determined parameters are B0′ = 1.41808 ± 0.00020 cm−1, gr = − 1.234 ± 0.025 × 10−4, gL = 0.999866 ± 0.000010, χAd = − 4.68 ± 0.94 × 10−29erg/molecule, where the symbols are defined in the text. The quoted uncertainties (except for gL) represent two standard errors and correspond to about a 95% confidence limit inclusive of parameter correlation effects.