Fine-structure spectrum of the FO radical, observed by far-infrared laser magnetic resonance

Abstract

The fine-structure transition Π1/22←2Π3/2 of the free radical FO has been detected by far-infrared laser magnetic resonance. All the observed transitions are magnetic dipole in character. The spin–orbit constant A0 has been determined experimentally; its value of −196.108 686(50) cm−1 is consistent with previous estimates. The analysis of a set of 290 transitions leads to the determination of a number of molecular parameters including rotational, centrifugal distortion, spin–orbit, lambda-doubling, magnetic hyperfine, and Zeeman terms. All four magnetic hyperfine structure constants a, bF, c, d for the F19 nucleus have been determined and are discussed in terms of the expectation values of the appropriate operators over the electronic wave function.