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Abstract: Using pulsed jet chirped-pulse, and cavity-based Fourier transform microwave spectroscopies over 900 transitions have been recorded for the title molecule in the 1–4GHz and 8–18GHz regions. The and carbon-13 species have been observed in natural abundance allowing a substitution structure for the CCC backbone to be determined. Nearly all the transitions observed were either a-type R branches or b-type Q branches. No c-type transitions were observed consistent with only the trans conformer being present under our experimental conditions. The and components of the iodine nuclear quadrupole coupling tensor have been determined. Of note, several forbidden, transitions, and one transition were observed with quite reasonable intensity. These observations have been rationalized through considerations of near degeneracies between energy levels connected via a large value (≈1GHz). [Copyright &y& Elsevier]

Abstract: The pure rotational spectrum of tin monochloride, SnCl, has been measured and analyzed using chirped pulse and cavity Fourier transform microwave spectrometers equipped with a laser ablation source. SnCl, in its electronic state, has been measured in the 8–17GHz region. Rotational constants, centrifugal distortion constants, Λ-doubling constants, magnetic hyperfine constants, and nuclear electric quadrupole coupling constants for multiple isotopologues have been determined and are reported. The bond length, nuclear magnetic and quadrupole constants have been analyzed and compared against the family of tetral halides. Analysis of the bond length and hyperfine interactions point to a Sn–Cl single bond which is largely ionic in nature. [Copyright &y& Elsevier]

Abstract: Two aluminum mirrors with radii of 203.2mm and radii of curvature also of 203.2mm have been used to construct a tunable Fabry–Perót type resonator with Q values of ∼200 at frequencies as low as 500MHz. The resonator has been incorporated into a pulsed nozzle, Fourier transform, Balle–Flygare spectrometer typically used for recording pure rotational spectra in the microwave region. The resonator design allows the instrument to access the radio frequency region (⩽3GHz) of the electromagnetic spectrum. The spectrometer is of use in (i) recording low J transitions of large asymmetric molecules where the spectra are often greatly simplified compared to higher frequency regions; (ii) measuring hyperfine constants for heavy molecules with higher accuracy than may be obtained at higher frequencies where hyperfine structure may not be resolvable; and (iii) provides further synchronicity between laboratory based measurements and radio astronomy in the 30cm region. The resonators use is illustrated by recording the rotational spectra of bromobenzene and iodobenzene. The lowest ΔJ =+1 transition for iodobenzene has been observed at 1130.5292(10)MHz. [Copyright &y& Elsevier]