A Fabry–Perót type resonator tunable below 2GHz for use in time domain rotational spectroscopy: Application to the measurement of the radio frequency spectra of bromobenzene and iodobenzene

New measurements and global analysis of rotational spectra of Cl-, Br-, and I-benzene: Spectroscopic constants and electric dipole moments

“…Predictions based on earlier work also facilitated supersonic expansion measurements. The first such measurements are presently reported for chlorobenzene, while for bromobenzene and for iodobenzene the previous data [9,10] are considerably extended. All available measurements, new and literature, hyperfine resolved and hyperfine unresolved, were collected into a single data set for each molecule, and subjected to a global fit by using the SPFIT program [18,19].…”

“…Nevertheless, it is only for fluorobenzene [7] that the high-resolution results from contemporary supersonic expansion Fourier transform microwave spectroscopy (FTMW) have been combined with high-J measurements in the mm-wave (MMW) rotational spectrum. For chlorobenzene some MMW [8], but not FTMW results are available, whereas for bromobenzene [9,10] and iodobenzene [10] the FTMW and not the MMW spectrum has been studied. We presently systematically extend the experimental information to allow determination of spectroscopic constants for all monohalogenobenzenes at the level of precision allowed by contemporary rotational spectroscopy.…”

The pure rotational spectrum of pivaloyl chloride, (CH3)3CCOCl, between 800 and 18800MHz

“…A brief description of these spectrometers is given below, but they are all well described in other literature [13][14][15][16][17][18]. All measurements presented in this work were performed at the University of North Texas.…”

“…These mirrors are tuned in the same fashion as the Fabry-Perót resonator used in the Balle-Flygare-type spectrometer. According to previous work, this spectrometer works best for very low frequency transitions and, prior to this work, was reported as measuring transitions down to as low as 1.1 GHz, something quite advantageous for heavy molecules with many low frequency transitions [15]. However, spectra at these frequencies can still be quite challenging to acquire due to difficulties in tuning and instrument sensitivity.…”

“…The second set of experiments were carried out on an instrument with a cavity and circuit design described by Etchison et al [15]. Briefly, this design incorporates the use of a cavity resonator that has hemispherical mirrors.…”