Buffer gas cooling for sensitive rotational spectroscopy of ice chemistry: A proposal

Highlights: • Chemistry in ice is an important component of interstellar and atmospheric chemistry. • Broadband rotational spectroscopy has not been applied to interrogate this chemistry. • Buffer gas cooling enables such investigations for molecules generated in ice. High temperatures and associated poor rotational partition functions have hindered the application of high-resolution rotational spectroscopy for detection of molecules desorbing from an ice substrate. Here, an experimental approach is presented which will enable such investigations through incorporation of a buffer gas cooling cell. We discuss design considerations for this apparatus and the expected performance based upon OC³⁴S measurements made with a related spectrometer in a 14.7 K sampled uniform flow. We highlight specific applications of this technique including chiral sensing of molecules generated in an interstellar ice, and the synthesis of exotic species not amenable to generation in the gas-phase.