The extremely perturbed parallel band system occurring in the infrared spectrum of cyclopropane between ∼3060 and 3150 cm-1 has been recorded with effective resolution of less than one-half of the Doppler width using a difference-frequency laser spectrometer and subsequent deconvolution. The region of the strong Q branches near 3101 cm-1 has also been measured with a color center laser and optothermal detection in a molecular beam adiabatically cooled to ∼10 K. Three distinct sequences of parallel subbands are observed belonging to the antisymmetric CH stretching vibration ν6 of species A″2 in anharmonic plus Jz-type Coriolis resonances with two perturbing states identified as the A″2 A″1 components of the combinations ν2 + ν11⊣ + ν14± and 2ν132± + ν14±. A five-level Hamiltonian model has been used to interpret the observed spectrum and to adjust spectroscopic constants for the states involved and for their interactions. Additional local perturbations are observed in the spectrum.
All Science Journal Classification (ASJC) codes
- Atomic and Molecular Physics, and Optics
- Physical and Theoretical Chemistry