High resolution Fourier transform spectroscopy of CH2D2 in the region 2350–2650 cm−1: the bands ν5 + ν7, 2ν9, ν3 + ν4, ν3 + ν7 and ν5 + ν9

Abstract

The IR spectrum of the CH₂D₂ molecule has been measured in the region of 2350–2650 cm⁻¹ on a Bomem DA002 Fourier transform spectrometer with a resolution of 0.004 cm⁻¹ (FWHM, apodized) and analyzed with a Hamiltonian model which takes into account resonance interactions between all vibrational states in that region. More than 3000 transitions have been assigned to the bands 2ν₉, ν₃ + ν₄, ν₅ + ν₉, ν₅ + ν₇ and ν₃ + ν₇ using ground state combination differences from the known ground state parameters. A set of 115 spectroscopic parameters for the excited vibrational states is obtained from a least squares adjustment. This reproduces the 646 initial upper ro-vibrational energies used in the fit with a d_rms = 0.0036 cm⁻¹.