title: Observation of molecular hyperfine structure in the extreme ultraviolet: The HF C-X spectrum.
abstract: Clearly resolved hyperfine structure has been observed in the extreme ultraviolet (XUV) spectra of the C (1)Pi, v=0-X (1)Sigma(+), v=0 transition of H(19)F obtained through 1 XUV+1 UV resonance enhanced multiphoton ionization spectroscopy. The hyperfine splitting within the R-branch lines shows significant perturbations, which we attribute to mixing with the rotational levels of the nearby v=29 level of the B (1)Sigma(+) ion-pair state. A deperturbation analysis quantitatively explains the apparent variation of the fluorine magnetic hyperfine parameter a(F), for which a value of 4034(83) MHz was obtained by averaging over the values derived from the R(0)-R(4) lines, after correcting for the effects of the perturbations.
authors.affiliation: Department of Physics and Astronomy, Trent University, Peterborough, Ontario K9J 7B8, Canada.
authors.forename: Jeffrey N
authors.initials: JN
authors.lastname: Philippson
authors.forename: Ralph C
authors.initials: RC
authors.lastname: Shiell
authors.forename: Elmar
authors.initials: E
authors.lastname: Reinhold
authors.forename: Wim
authors.initials: W
authors.lastname: Ubachs