UF-CRDS/ UF-PAS

Cavity ring-down spectroscopy in uniform supersonic flows
Photoacoustic spectroscopy in a uniform supersonic flow
PhD student Yanan Liu with the Uniform Flow – Photoacoustic Spectroscopy instrument.

The Uniform-Flow Cavity Ring-Down Spectroscopy instrument is the first in the world to combine cw-CRDS with a Laval flow. With it we have demonstrated Simultaneous Kinetics and Ring-down (SKaR) in a Laval Flow, allowing a complete low temperature kinetics measurement to be obtained in 2 hours.

We have recently modified the instrument to perform the first Photoacoustic Spectroscopy under supersonic conditions. A schematic view of the configuration is shown below.

Schematic of UF-PAS instrument
Figure above shows a Doppler profile over the CH4 nu3 R0 line giving a temperature of `50 K in the argon flow.

Y. Liu, J. Khatri, S. Thawoos, N. Suas-David, A.G. Suits, “Photoacoustic Spectroscopy in a Supersonic Flow,”J. Phys. Chem. A (accepted).

S. Thawoos, G. E. Hall, N. Suas-David, A. G. Suits, “Contrast and complexity in the low temperature kinetics of CN(v=1) with O2and NO: Simultaneous kinetics and ringdown in a uniform supersonic flow,” J. Phys. Chem. A (X. Yang Festschrift). (2024) 128.29 5906-5924. DOI: 10.1021/acs.jpca.4c02737.

N. Suas-David, S. Thawoos and A. G. Suits, “A Uniform Flow – Cavity Ring-Down Spectrometer (UF-CRDS):  A new setup for spectroscopy and kinetics at low temperature,” J Chem. Phys. (2019) 151, 244202. https://doi.org/10.1063/1.5125574 (Featured Article)