High resolution FTIR spectroscopy on CH₂DI and CHD₂I: analyses of the fundamental bands ν_6' and ν_6''

Abstract

The H–C–I and D–C–I deformations, i.e. ν_6' and ν_6″ fundamental vibration bands of the methyl iodide molecules CH₂DI and CHD₂I have been investigated with high resolution (0.001 cm⁻¹) Fourier transform infrared spectra in the region 600–1000 cm⁻¹ for CH₂DI and 550–850 cm⁻¹ for CHD₂I. For CH₂DI ν_6′ appears as a hybrid a/b-type band and ν_6″ as a c-type band. For CHD₂I the corresponding types are hybrid a/c and b. We have been able to assign more than 12 000 transitions in the case of CH₂DI and over 11 000 transitions in the case of CHD₂I. The upper and ground state parameters have been obtained by fitting these transitions to the A reduced Watson's Hamiltonian. The interactions between the states v_6′=1 and v_6″=1 have also been investigated.

Acknowledgement

The authors acknowledge the Academy of Finland for financial support.