IR Laser Evaporation of Phenol Solvated with Water Molecules from Liquid Beam of Aqueous Phenol Solution

Abstract

A continuous liquid flow in a vacuum (liquid beam) of an aqueous solution of phenol was irradiated with an IR laser at 2.92 μm, 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 product ions were solvated phenol cluster ions, Phenol+ (H2O)m (m = 0−4). The mechanism of the cluster ion formation was investigated by measuring the abundances of the product ions as a function of the IR laser power, the UV laser power, and the delay time between an IR laser pulse and the subsequent UV laser pulse. It was concluded that phenol and its hydrated clusters are isolated within several microseconds from the liquid beam due to selective excitation of the solvent water molecules under irradiation of an IR laser having a fluence of less than 1100 mJ pulse-1 cm-2.