Detailed study of fine and hyperfine structures in rotational spectra of the free fluoroformyloxyl radical FCO2⋅

Abstract

More than 160 new hyperfine components of rotational transitions of the free fluoroformyloxyl radical FCO(2) have been measured using the Prague millimeter wave high resolution spectrometer. The frequencies of these transitions together with the previously measured data were analyzed in detail and precise values of magnetic hyperfine and fine parameters were obtained. These new parameters significantly improve the values of previously determined hyperfine parameters which were rather unreliable. The new fine and hyperfine parameters obtained in this study are compatible with those of the simultaneously electron paramagnetic resonance study. Besides that, significantly improved ground state rotational and centrifugal distortion constants of the fluoroformyloxyl radical were derived.

High-resolution FTIR study of the CO stretching band ν4 of the fluoroformyloxyl radical, FCO2

“…This radical has recently been detected by high-resolution millimetre-wave and infrared spectroscopy in the gas phase [10][11][12]. The latter millimetre-wave study [12] includes details on the fine and hyperfine structures that are supported by the recent analysis of the electron paramagnetic resonance (EPR) spectrum of FCO 2 [13]. The first high-resolution analysis of the m 2 band (970.2 cm À1 ) was also reported [14].…”

“…A weighted nonlinear least-squares fit was performed, using vibrational ground state constants fixed at previously determined millimetre wave values [12]. Unitary weights were given to isolated lines, whereas for lines with multiple assignments, the transitions were intensity-weighted.…”

“…Argüello et al have reported [9] the analysis of the visible and IR spectra of FCO 2 isolated in inert gas matrices, leading to the assignment of all six fundamental vibrations on the basis of C 2v symmetry. This radical has recently been detected by high-resolution millimetre-wave and infrared spectroscopy in the gas phase [10][11][12]. The latter millimetre-wave study [12] includes details on the fine and hyperfine structures that are supported by the recent analysis of the electron paramagnetic resonance (EPR) spectrum of FCO 2 [13].…”

“…It is believed that this work will favor its spectroscopic detection in the upper atmosphere in the near future. This analysis awaited the accurate determination of the molecular constants of the radical in theX 2 B 2 ground electronic state that are now available [10][11][12].…”

Rotational spectrum of 13C chloromethanes

“…The optical path length of a conventional glass 280 cm long cell was doubled using a roof top mirror and a polarization grid as described in [6,7]. The sample pressures were measured by a capacitance gauge from Leybold with relative uncertainty about 5%.…”