Submillimeter-Wave Spectra of H2Cl+ and its Isotopic Species: Molecular Structure

Abstract

The rotational spectra of HD35Cl+, H235Cl+, and H237Cl+ were measured in the frequency region of 180 to 550 GHz with a source-modulated submillimeter-wave spectrometer. The ions were generated in a free space absorption cell by a hollow-cathode discharge in a gas mixture of Cl2 and He to which H2 and/or D2 was added. Precise molecular constants including the electric quadrupole coupling constants were determined for the three species. The zero-point average structure, rz, was calculated from moments of inertia corrected for harmonic terms. The harmonic force field of H2Cl+ was derived from previously estimated harmonic vibrational frequencies and inertial defects. The rz structures obtained are rz(Cl–H)=1.320 57(48)Å and θz(H–Cl–H)=94.238(72)° for H235Cl+ and rzCl–H)=1.320 60(38)Å and θz(H–Cl–H)=94.239(58)° for H237Cl+, where values in parentheses indicate errors due to residual inertial defects among the corrected moments of inertia. When the θz of HD35Cl+ is assumed to be the same as that of H235Cl+, the rz(Cl–H) and rz(Cl–D) lengths of HD35Cl+ are calculated to be 1.320 69(69) Å and 1.316 54(111) Å, respectively

The Chemistry of Interstellar Molecules Containing the Halogen Elements

“…The lowest lying rotational transition, the 2 Π 3/2 J = 5/2 → 3/2 multiplet near 207.6 μm, lies in a wavelength range accessible to the HIFI instrument on the Herschel Space Observatory. The rotational spectrum of H 2 Cl + has also been the subject of a laboratory study at high spectral resolution; here, the measurements of Araki et al (2001) indicate that the lowest lying rotational line of ortho-H 2 Cl + , the 1 10 − 1 01 transition, lie near 189.2 and 188.4 GHz respectively for the H 35 2 Cl + and H 37 2 Cl + isotopologues. (These transitions are split into six and four hyperfine components, covering ∼56 and 14 MHz, respectively.)…”

Detection of chloronium and measurement of the35Cl/37Cl isotopic ratio atz= 0.89 toward PKS 1830–211

“…The chloronium frequencies and relative intensities of the hyperfine components are taken from the work by Araki et al (2001). The dipole moment, μ = 1.89 D, is from an ab initio calculation by Müller (2008).…”

HERSCHELOBSERVATIONS OF INTERSTELLAR CHLORONIUM. II. DETECTIONS TOWARD G29.96-0.02, W49N, W51, AND W3(OH), AND DETERMINATIONS OF THE ORTHO-TO-PARA AND35Cl/37Cl ISOTOPIC RATIOS

“…Table 1 lists, for each target, the coordinates, distance, Herschel observation identifiers (OBSID), observed continuum brightness temperatures, and source systemic velocity relative to the local standard of rest (LSR). Müller et al 2005), which are based on laboratory spectroscopy performed by Araki et al (2001) and a theoretical estimate of the dipole moment by Müller (2008). Because 35 Cl and 37 Cl both possess a nuclear spin of 3/ 2, the 2 1 12 01 -transition is split into eight hyperfine components and the 1 0 11 00 -transition into three.…”