Abstract
Infrared spectroscopy combined with the matrix isolation method, where samples are trapped by a cold and inert-molecular solid, has been used for the investigations of small water clusters. After the descriptions of the stable structures and vibrations of the clusters, the author explains experimental techniques of the matrix isolation and demonstrates recent works on the clusters isolated in the solids of rare gases, para-hydrogen, and methane as well as the hydrogen adsorption layer on a vapor deposited NaCl film. The relation between the frequency shift of the hydrogen-bonded OH stretch and the matrix critical-temperature is also shown.
