Determination of the Energy Structure and Spectroscopic Parameters of the Vibrational State ($${{{v}}_{5}}$$ = $${{{v}}_{{12}}}$$ = 1) of the C2D4 Molecule

Using a Bruker IFS 125HR Fourier spectrometer, the vibrational-rotational structure of the $${{\nu }_{5}} + {{\nu }_{{12}}}$$ band of the C2D4 molecule has been detected for the first time with a resolution of 0.0025 cm–1. At the initial investigation stage, interpretation of transitions in the spectrum is carried out; at a later stage, results of the interpretation are used as experimental data for solving the inverse spectroscopic problem. The set of 12 spectroscopic parameters of the vibrational state under study is determined for the first time. The root-mean-square deviation amounts to 0.0013 cm–1.