High resolution spectroscopic study of C2H4: Re-analysis of the ground state and ν4, ν7, ν10, and ν12 vibrational bands

We report here the results of high accurate, (1−2)×10−4cm−1, ro-vibrational analysis of the ethylene molecule in the region of 640-1535 cm−1. More than 1110, 5060, 4670, and 2900 transitions belonging to the ν4, ν7, ν10, and ν12 bands were assigned in the experimental spectrum with the maximum values of quantum numbers Jmax./Kamax., equal to 36/11, 50/21, 40/17 and 48/17, respectively. Rotational and centrifugal distortion parameters of the ground vibrational state were improved on the basis of assigned transitions and high accurate saturated absorption experimental data known from the literature. The inverse spectroscopic problem was solved for the set of strongly interacting (v4=1)/(v7=1)/(v10=1)/(v12=1) states. The set of 78 parameters obtained from the fit reproduces values of 3644 initial “experimental” ro-vibrational energy levels (more than 13,740 assigned transitions of the ν4, ν7, ν10, and ν12 bands) with the rms=0.00023 cm−1. In this case, the 197 high accurate saturated absorption transitions are reproduced with the rms=18.5 kHz.

► High resolution re-analysis of the ground vibrational state. ► High resolution re-analysis of the v4, v7, and v10 vibrational bands. ► Increasing about two times information about the v4, v7, and v10 bands. ► Determination and improvement of spectroscopic parameters of studied bands.