Laser Desorption Jet-Cooling Spectroscopy of Organic Molecules

Laser desorption coupled with mass selective detection enables a sensitive detection of molecules, desorbed from a surface without fragmentation. Additional selectivity is obtained when the desorption is performed in the expansion region of a supersonic free jet. In this approach the internal degrees of freedom of the desorbed species are cooled down by multiple collisions, the desorbed molecules are brought into the detection region with a high efficiency, and both mass selective and wavelength selective detection can be performed using a Resonance Enhanced Multi Photon Ionization (REMPI) detection scheme.