POSTIONIZATION OF MOLECULES DESORBED FROM SURFACES BY KEV ION-BOMBARDMENT WITH FEMTOSECOND LASER-PULSES

We report the use of femtosecond laser photoionization of sputtered ne utral molecules to enhance the sensitivity of detection and to improve the prospects for molecule-specific imaging experiments. Results are presented for patterned metal oxides, polycyclic aromatic hydrocarbons and several amino acids. In addition to increased signal levels, we f ind that fs photoionization generally yields simpler mass spectra than the corresponding SIMS spectra, although considerable fragmentation i s observed in both cases. (C) 1998 John Wiley & Sons, Ltd.