The Pure Rotational Spectra of Diatomics and Halogen-Addition Benzene Measured by Microwave and Radio Frequency Spectrometers

Two aluminum spherical mirrors with radii of 203.2 mm and radii of curvature also of 203.2 mm have been used to construct a tunable Fabry-Perót type resonator operational at frequencies as low as 500 MHz. The resonator has been incorporated into a pulsed nozzle, Fourier transform, Balle-Flygare spectrometer. The spectrometer is of use in recording low J transitions of large asymmetric molecules where the spectra are often greatly simplified compared to higher frequency regions. The resonators use is illustrated by recording the rotational spectra of bromobenzene and iodobenzene. In related experiments, using similar equipment, the pure rotational spectra of four isotopomers of SrS and all three naturally occurring isotopomers of the actinide-containing compound thorium monoxide have been recorded between 6 and 26 GHz. The data have been thoroughly analyzed to produce information pertaining to bond lengths and electronic structures

HYPERFINE STRUCTURE IN THE PURE ROTATIONAL SPECTRUM OF 208^{208}Pb35^{35}Cl

Author Institution: Department of Chemistry, University of North Texas, 1155 Union Circle \#305070, Denton, Tx 76203-5017, U.S.AInitially in our laboratory the pure rotational spectrum of the title molecule was studied using a Balle-Flygare Fourier transform microwave spectrometer. Analysis was troublesome and so the spectrum was remeasured using a chirped pulse Fourier transform microwave (CP-FTMW) spectrometer. The correct intensity aspect of the CP-FTMW experiment allowed succesful quantum number assignments for the hyperfine structure for the correct isotopologue. Spectroscopic constants have been obtained from a fit to a data set consisting of our measurements combined with those of a prior study on the $X_2^2\Pi_{\frac{3}{2}} \rightarrow X_1^2\Pi_{\frac{1}{2}}$ fine structure transitions nderline{\textbf{191}} 108, 1998.}