First-principles calculations of infrared spectra for three ethylene isotopologues: 13C2H4, 13C12CH4 and 12C2H3D

Abstract Accurate variational high-resolution spectra calculations are reported for the very first time for three ethylene isotopologues, namely 13 C 2 H 4 , 13 C 12 CH 4 and 12 C 2 H 3 D, of symmetry D 2 h , C 2 v and C s . Theoretical infrared spectra predictions are given at 296 K in the range [0 - 4500] cm − 1 up to J max = 40, 35 and 30, respectively. Calculations are performed using the normal-mode Eckart-Watson Hamiltonian as well as accurate potential and dipole moment surfaces initially derived for the main isotopologue 12 C 2 H 4 . The construction of the complete line lists is carried out by means of isotopic and symmetry transformations corresponding to the 12 C →  13 C and H  →  D substitutions. This work will be useful for future spectral intensity analysis and all line lists will be available in the TheoReTS information system ( http://theorets.univ-reims.fr , http://theorets.tsu.ru ).