Infrared spectroscopy and enclosive flow cooling: concept of an integrated multireflection optics

Abstract

Molecules with more than four atoms generally exhibit relatively complex vibration-rotation spectra at standard conditions. Therefore the assignment of individual spectral lines is often impossible. Furthermore, these molecules are difficult to detect in trace concentrations by absorption spectroscopy with tunable diode lasers. A simplification of the spectrum can be achieved by supercooling the gas. For that purpose, the enclosive flow cooling technique was developed which has a very high optical absorption efficiency compared to supersonic jet cooling and proved to be robust and easy to manage. To further enhance the detection sensitivity of the method, a multireflection optics is integrated into the cooling cell. The concept of the advanced cooling cell is presented.