Matrix-isolation spectroscopy using solid parahydrogen as the matrix: Application to high-resolution spectroscopy, photochemistry, and cryochemistry

Solid parahydrogen is an excellent matrix for matrix-isolation spectroscopy. First, spectroscopic resolution exceeds the resolution attainable in conventional matrices so that detailed analysis of rotational structure of molecules in the solid phase may be performed in favorable cases. Secondly, in situ photolysis is feasible on account of the subduction of the cage effect in solid parahydrogen, which is in sharp contrast to the system in rare gas matrices. In this Account we describe 1) relevant properties of solid parahydrogen in connection with its use as the matrix, 2) outlines of experimental procedures using solid parahydrogen as the matrix, 3) examples of high-resolution spectroscopic studies, and 4) examples of studies on photochemistry and cryochemistry.