The rotational and fine-structure spectrum of FeH, studied by far-infrared laser magnetic resonance

Transitions between the spin-rotational levels of the FeH radical in the υ=0 level of the X4Δ ground state have been detected by the technique of laser magnetic resonance at far-infrared wavelengths. Both pure rotational and fine-structure transitions have been observed; lambda-type doubling is resolved on all the observed transitions. The energy levels of FeH are strongly affected by the breakdown of the Born-Oppenheimer approximation and cannot be modeled accurately by an effective Hamiltonian. The data are therefore fitted to an empirical formula to yield term values and g factors for the various spin-rotational levels involved. Many of the resonances show a doubling that arises from the proton hyperfine structure.Copyright 2006 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. Citation: Brown, J. M. et al. (2006). 'The rotational and fine-structure spectrum of FeH, studied by far-infrared laser magnetic resonance', The Journal of Chemical Physics 124, 234309. The article can be found at http://link.aip.org/link/?JCPSA6/124/234309/1