IR laser evaporation of phenol solvated with water molecules from liquid beam of aqueous phenol solution

A continuous liquid flow in a vacuum (liquid beam) of an aqueous solution o f phenol was irradiated with an IR laser at 2.92 mum, and species from the liquid beam surface were ionized by a UV laser at 266 nm and mass-analyzed by a time-of-flight mass spectrometer. The mass spectra showed that the pro duct ions were solvated phenol cluster ions, Phenol(+) (H2O)(m) (m = 0-4). The mechanism of the cluster ion formation was investigated by measuring th e abundances of the product ions as a function of the IR laser power, the U V laser power, and the delay time between an IR laser pulse and the subsequ ent UV laser pulse. It was concluded that phenol and its hydrated clusters are isolated within several microseconds from the liquid beam due to select ive excitation of the solvent water molecules under irradiation of an IR la ser having a fluence of less than 1100 mJ pulse(-1) cm(-2).