High-resolution spectroscopy of CHD: Line positions and energy structure of the strongly interacting ν,ν,ν,ν and ν bands.

High resolution infrared spectra of CHD were recorded in the region of 550-1950 cm with a Bruker IFS125 HR Fourier transform infrared spectrometers and rotational structures of the five lowest strongly interacting ν, ν,ν,ν and ν bands were analyzed. The number of about 28000 transitions (4200/6800/5600/5000/6400 for the bands ν,ν,ν,ν and ν) with J = 40 and K = 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 ν 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 d=1.7×10 cm; the initial nonsaturated, unblended and not very weak of 28000 assigned transitions are reproduced with the d=2.2×10 cm. Ground state parameters of the CHD molecule were improved as well.