High–resolution spectroscopy of C2H3D: Line positions and energy structure of the strongly interacting [formula omitted] and [formula omitted] bands

Abstract

High resolution infrared spectra of C2H3D were recorded in the region of 550–1950 cm−1 with a Bruker IFS125 HR Fourier transform infrared spectrometers and rotational structures of the five lowest strongly interacting ν10, ν7,ν8,ν4 and ν6 bands were analyzed. The number of about 28000 transitions (4200/6800/5600/5000/6400 for the bands ν10,ν7,ν8,ν4 and ν6) with Jmax = 40 and Kamax = 20 were assigned to these five bands. The weighted fit of 3990 upper energy values obtained from the experimentally recorded transitions was made with a Hamiltonian which takes into account resonance interactions between all studied bands as well as with the sixth ν3 band which was considered in this case as a “dark” one. As the result of analysis, a set of 279 fitted parameters was obtained which reproduces the initial 3990 upper “experimental” ro–vibrational energy values with the drms=1.7×10-4 cm−1; the initial nonsaturated, unblended and not very weak of 28000 assigned transitions are reproduced with the drms=2.2×10-4 cm−1. Ground state parameters of the C2H3D molecule were improved as well.