FTIR study of 11 interacting vibrational states of CH2DI

Rotational level structure of 12 vibrational states of CH₂DI with energies in the 1000-1800 cm⁻¹ region has been retrieved from high resolution (0.001-0.003 cm⁻¹) FTIR spectra. Eleven vibrational states, namely, 2¹, 3¹6¹(A′), 5¹(A′′), 3¹6¹(A′′), 6²(A′), 5¹(A′), 6¹(A′) 6¹(A′′), 2¹3¹, 6²(A′′), 3²6¹(A′) and 3¹5¹(A′′) have been found to interact. A total of 27 919 transitions belonging to diverse fundamental, combination and hot bands were assigned and used in the combined nonlinear root mean square fit to give the band centers, rotational, centrifugal distortion and coupling parameters of the states under investigation. The RMS deviation of the fit has been demonstrated to be 0.000218 cm⁻¹. The number of the coupling parameters required to reproduce the observed spectra with the experimental uncertainty appeared to be 46.