Chirped-pulse Fourier Transform Microwave Spectroscopy Research Articles

Chirped-pulse fourier transform microwave spectroscopy of the simple chiral compound bromofluoroacetonitrile, CHBrFCN

Pulsed jet chirped-pulse Fourier transform microwave spectroscopy has been used to record 264 transitions for the 79-Br species and 239 transitions for the 81-Br species of the title molecule. Measurements have been made in the 8–14 GHz regions. The complete 79-Br, 81-Br and N quadrupole coupling tensors have been determined for the first time.

The rotational spectrum of epifluorohydrin measured by chirped-pulse Fourier transform microwave spectroscopy

The rotational spectrum of epifluorohydrin measured by chirped-pulse Fourier transform microwave (CP-FTMW) spectroscopy is presented. A new CP-FTMW spectrometer capable of measuring the entire 7.5–18.5 GHz spectrum with a single polarizing pulse is described briefly. The CP-FTMW spectrometer takes advantage of recent advances in digital electronics by utilizing a 4.2 GS/s arbitrary waveform generator as a frequency source and a 12 GHz digital oscilloscope to digitize the down converted molecular free induction decay (FID). Signal averaging in the time domain is used to increase the signal-to-noise ratio. The rotational constants of three unique conformers of epifluorohydrin were measured, as well as the rotational constants of the three unique 13C isotopomers and the 18O isotopomer (in natural abundance) of the most stable conformer. The rotational constants of the two less stable conformers differ significantly from those previously reported [F.G. Fujiwara, J.L. Painter, H. Kim, J. Mol. Struct. 41 (1977) 169–175]. Ab initio calculations were performed for all three conformations and are compared to experimental values.