LOCAL MODE INTERPRETATION OF THE CH AND CD STRETCHING VIBRATIONAL MANIFOLDS OF ISOTOPIC ETHYLENES, C2H3D AND C2HD3

The IR spectra of C2H3D and C2HD3 have been studied up to 3 quanta of excitation of CH and CD stretching (<9500 cm-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 C2H3D and 33 in C2HD3 are in excellent agreement with each other, and also with those determined for other isotopic ethylenes.