PICOSECOND LASER-DESORPTION KINETICS OF POLY-(ETHYLENE GLYCOL)

For ethylene glycol and poly-(ethylene glycol) oligomers (PEGs) with a verage masses of 600 and 1500 Da, translational energy distributions f ollowing picosecond laser desorption from a silica surface were determ ined for two different laser fluences. Desorption and dissociation are found to be well described by thermal equilibrium kinetics even for h eating rates exceeding 10(13) K/s. For the intact desorption of monola yer coverages of PEGs from silica surfaces, picosecond laser heating w as found to be less efficient than classical heating. (C) 1997 Elsevie r Science B.V.