High resolution infrared spectroscopy of [1.1.1]propellane: The region of the ν9 band
The region of the infrared-active band of the ν9 CH2 bending mode [1.1.1]propellane has been recorded at a resolution (0.0025 cm-1) sufficient to distinguish individual rovibrational lines. This region includes the partially overlapping bands ν9 (e') = 1459 cm-1, 2ν18 (l = 2, E') = 1430 cm-1, ν6 + ν12 (E') = 1489 cm-1, and ν4 + ν15 (A2") = 1518 cm-1. In addition, the difference band ν4 - ν15 (A2") was observed in the far infrared near 295 cm-1 and analyzed to give good constants for the upper ν4 levels. The close proximities of the four bands in the ν9 region suggest that Coriolis and Fermi resonance couplings could be significant and theoretical band parameters obtained from Gaussian ab initio calculations were helpful in guiding the band analyses. The analyses of all four bands were accomplished, based on our earlier report of ground state constants determined from combination differences involving more than 4000 pairs of transitions from five fundamental and four combination bands. This paper presents the analyses and the determination of the upper state constants of all four bands in the region of the ν9 band. Complications were most evident in the 2ν18 (l = 2, E') band, which showed significant perturbations due to mixing with the nearby 2ν18 (l = 0, A1') and ν4 + ν12 (E') levels which are either infrared inactive as transitions from the ground state, or, in the latter case, too weak to observe. Finally, these complications are discussed and a comparison of all molecular constants with those available from the ab initio calculations at the anharmonic level is presented.
- Research Organization:
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Environmental Molecular Sciences Lab. (EMSL)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC05-76RL01830
- OSTI ID:
- 1001115
- Report Number(s):
- PNNL-SA-73401; 20907; KP1704020; TRN: US201101%%767
- Journal Information:
- Journal of Molecular Spectroscopy, Vol. 264, Issue 1; ISSN 0022-2852
- Publisher:
- Elsevier
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
HYDROCARBONS
INFRARED SPECTRA
CORIOLIS FORCE
FERMI RESONANCE
GROUND STATES
RESOLUTION
SPECTROSCOPY
ENERGY-LEVEL TRANSITIONS
Propellane
High resolution infrared spectrum
Rovibrational constants
Ab initio DFT study
Anharmonic frequencies
Environmental Molecular Sciences Laboratory