Rotational Spectrum of a Dark State in 2-Fluoroethanol Using Microwave/Radiofrequency-Infrared Multiple Resonance.

摘要

Microwave/radiofrequency-infrared multiple resonance has been used with an electric-resonance optothermal spectrometer to characterize a weak 21.6 MHz perturbation in the infrared spectrum of the v14 C-O stretching vibration of 2-fluoroethanol. The infrared spectrum of 2-fluoroethanol was recorded at a resolution of approx. 2 MHz using a tunable microwave-sideband CO2 laser. The spectrum is fit by an asymmetric-rotor Hamiltonian to a precision of 0.6 MHz, except for the transitions to the 4(13) upper state which are split into doublets by an interaction between the 4(13) level and a rotational level of a nearby background, or dark, vibrational state.