TIME-RESOLVED PHOTOFRAGMENTATION OF AU-15(+) CLUSTERS

Au-15(+) ions were produced by laser vaporization and transferred into a Penning trap. They were illuminated by a 10 ns dye-laser pulse at p hoton energies covering the range from 2.7 to 4.4 eV. Besides the dete rmination of fragmentation patterns and photoabsorption cross sections the monomer evaporation of the excited clusters was observed time res olved on a microsecond to millisecond timescale yielding a monomer sep aration energy of 1.95(5) eV. In addition, the dissociation energy for Au-14(+) could be determined as 1.57(5) eV by time resolved investiga tion of the sequential decay Au-15(+) --> Au-14(+) + Au --> Au-13(+) 2 Au.