title: The fluoroformyloxyl radical geometry and ground-state rotational spectra of the free FC18O2· radical.
abstract: The rotational spectra of the isotopically substituted free fluoroformyloxyl radical FC(18)O(2·) were measured using the Prague millimeter-wave high-resolution spectrometer. More than 110 rotational-fine-hyperfine transition lines were observed and assigned to appropriate quantum numbers in the frequency range of 235-270 GHz. The obtained transition frequencies were analyzed with standard effective Hamiltonians to acquire a set of precise rotational, centrifugal-distortion, fine, and hyperfine structure molecular constants. Merging the new FC(18)O(2·) isotopologue molecular parameters with those previously obtained for the ordinary FC(16)O(2)[middle dot] radical, the substitution molecular geometry in the ground vibronic state was evaluated. The molecular parameters for both radical isotopologues were also calculated by several quantum chemistry methods and their calculated mutual ratios are in remarkable agreement with the experimental FC(16)O(2·)/FC(18)O(2·) parameter ratios. The measurements, assignments of the 18-oxygen isotopologue FC(18)O(2·) radical millimeter-wave transitions, as well as the derivation of the fluoroformyloxyl radical ground-state geometry have been carried out for the first time.
authors.affiliation: Department of Analytical Chemistry, Institute of Chemical Technology, Technická 5, 166 28 Prague 6, Czech Republic. jan.koucky@vscht.cz
authors.forename: Jan
authors.initials: J
authors.lastname: Koucký
authors.forename: Lucie
authors.initials: L
authors.lastname: Kolesniková
authors.forename: Tereza
authors.initials: T
authors.lastname: Uhlíková
authors.forename: Juraj
authors.initials: J
authors.lastname: Varga
authors.forename: Patrik
authors.initials: P
authors.lastname: Kania
authors.forename: Helmut
authors.initials: H
authors.lastname: Beckers
authors.forename: Helge
authors.initials: H
authors.lastname: Willner
authors.forename: Štěpán
authors.initials: Š
authors.lastname: Urban