Yingchun Guo

The absorption spectra of H2O+ and D2O+ in the visible and near infrared region

The absorption spectra of the electronic transition of H2O+ and D2O+ are investigated in the visible region from 16 400 to 17 600 cm−1 and in the near infrared region from 12 200 to 14 000 cm−1 using optical heterodyne magnetic rotation enhanced velocity modulation spectroscopy (OH-MR-VMS). Three subbands including 111 spectral lines of H2O+ and seven subbands including 209 spectral lines of D2O+ are observed and analysed, among which four subbands, Σ (0,9,0)−(0,0,0), Δ (0,9,0)–(0,0,0), Π (0,8,0)–(0,0,0) and Π (0,10,0)–(0,0,0) of D2O+ in the near infrared region are studied for the first time. Holding the molecular constants of the lower state fixed at the published values, a set of molecular constants and rotational energy terms for each observed vibronic level of the upper state are obtained.

Concentration modulation laser spectroscopy of the C2 molecule Swan (d 3∏ g ←a 3∏ u ) system

Abstract The rotational structure of the C2 molecule Swan (d 3∏ g ←a 3∏ u ) system (0,1) band has been recorded by optical heterodyne magnetic rotation enhanced concentration modulation laser spectroscopy in the range of 17730–17880 cm−1. The C2 molecule is generated by an electric discharge through a mixture of acetylene and argon gas and a well-resolved spectrum is recorded with an absolute accuracy of 0.007 cm−1. Sensitivity of the method enables us to observe not only the traditionally observed branches of Δω = 0 sub-bands but also some Δω≠0 transitions, providing a slight improvement in the accuracy of some molecular constants of the two states. The theoretical spectra are simulated using the effective Hamiltonian of Brown and Merer and directly fitted to observed spectra; rotational parameters are derived from this fit for the two 3∏ states.