THE J = 1–0 TRANSITIONS OF ¹² CH ⁺ , ¹³ CH ⁺ , AND ¹² CD ⁺

Abstract

A new set of laboratory experimental frequencies for the J = 1-0 rotational transition of 12 CH + , 13 CH + , and 12 CD + are obtained by using a liquid nitrogen cooled extended negative glow discharge in a gas mixture of CH 4 and He. These frequencies are found to be significantly different from those reported previously. The unexpectedly large Zeeman effect and the spin-rotation hyperfine interaction for a 1 Σ molecule are observed. The Zeeman effect and the hyperfine interaction appear to be distinctively different for each isotopic species. Theoretical considerations reveal the isotopic dependence of the magnitudes of these effects, and they also provide strong evidence for the identifications.

Communication: Rotational g-factor and spin-rotation constant of CH+

“…18 The measured spin-rotation constant was found to agree well with a calculated value of Sauer and Paidarová. 32 Their approach consisted of vibration-rotational averaging a spin-rotation radial function for 13 CH + calculated with the coupled-cluster singles and doubles polarization propagator approximation ͑CCSDPPA͒, 34 which is a precursor to the second-order polarization propagator approximation with coupled-cluster singles and doubles amplitudes method ͓SOPPA͑CCSD͔͒.…”

“…[1][2][3] To confirm this identification, its electronic, vibrational, and rotational transitions have also been studied in the laboratory. [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] Apart from its astrophysical importance, the CH + ion has also attracted much attention such as BH and AlH due to their unusual magnetic properties [20][21][22][23][24][25][26][27][28][29][30][31][32][33] similar to temperature independent paramagnetism, antishielding, a large spin-rotation constant of the carbon atom, and a large and negative rotational g-factor, which are rarely found in closed shell molecules.…”

The impact of recent advances in laboratory astrophysics on our understanding of the cosmos

“…The H 2 O + frequencies are given by Mürtz et al (1998). CH + data come from the spectroscopic work of Amano (2010). Lastly, there are numerous spectroscopic studies of NH and NH 2 , which have been compiled into the Cologne Database for Molecular Spectroscopy (Müller et al 2005).…”

CH+(1–0) and13CH+(1–0) absorption lines in the direction of massive star-forming regions

“…Appendix (page 6) is only available in electronic form at http://www.aanda.org recently did successful experiments provide accurate frequency determinations (Amano 2010). Moreover, ground-based astronomical detection of 12 CH + (1-0) is prevented by its proximity to a strong atmospheric line of water vapor.…”

“…We observed the J = 1−0 transitions of CH + and 13 CH + , with rest frequencies of 835.1375 and 830.2150 GHz (Amano 2010), in the upper and lower sidebands of the Band 3a HIFI receiver respectively, using the dual beam switch (DBS) mode and the wide band spectrometer (WBS) with a frequency resolution of 1.1 MHz. In these frequency ranges, the corresponding velocity resolution is ∼0.36 km s −1 , and the Herschel HPBW at 835.1 GHz is 26 .…”