First study of the ro-vibrational structure of the g-symmetry vibrational states of C2D4 from the analysis of hot bands: The ν7+ν10−ν10 and ν10+ν12−ν10 bands

- The first high resolution analysis of the weak hot bands, ν10+ν12−ν10 and ν7+ν10−ν10.
- Resonance interactions in the C2D4 molecule.
- Determination of spectroscopic parameters of the (v10=v12=1) and (v7=v10=1) states.

The two strongest absorption “hot” bands of C2D4, ν7+ν10−ν10 and ν10+ν12−ν10 were analyzed for the first time on the basis of high resolution infrared spectra recorded with a Bruker high resolution Fourier transform spectrometer. About 740 and 550 transitions (233 and 174 upper state ro-vibrational energy values) with Jmax.=25, Kamax=18 and Jmax.=20, Kamax.=10 for the bands ν7+ν10−ν10 and ν10+ν12−ν10 were assigned. The obtained upper ro-vibrational energies were used then in the weighted fit of parameters of the effective Hamiltonian which takes into account resonance interactions between the vibrational states (v7=v10=1) and (v10=v12=1), on the one hand, and eight other closely located vibrational states, on the other hand. A set of 46 varied parameters was obtained from the fit, which reproduces the initial experimental data with the rms deviation of 2.5×10−4cm−1 and which is close to experimental uncertainties.