Local mode interpretation of the CH and CD stretching vibrational manifolds of isotopic ethylenes, C2H3D and C2HD3

Abstract The IR spectra of C 2 H 3 D and C 2 HD 3 have been studied up to 3 quanta of excitation of CH and CD stretching ( −1 ). Observed vibrational wavenumbers are well reproduced in terms of a local mode model, which involves different Fermi resonance interactions in each molecule. Equivalent harmonic and anharmonic parameters determined from refinements to 65 vibration levels in C 2 H 3 D and 33 in C 2 HD 3 are in excellent agreement with each other, and also with those determined for other isotopic ethylenes.