ISSN:
1432-0649
Keywords:
PACS: 33.80.Eh; 36.40.-c; 42.65.Re
Source:
Springer Online Journal Archives 1860-2000
Topics:
Physics
Notes:
Abstract. A femtosecond photo-electron experiment is described which provides excellent conditions for measuring time-resolved photo-electron spectra of free, monodispersed cluster anions using repetition rates up to 100 Hz. Cluster anions are synthesized in an electric arc and subsequently cooled in a helium carrier gas. A time-of-flight spectrometer is used for mass separation of the negatively charged clusters. The kinetic energy of the photo-electrons is analyzed by a magnetic-bottle time-of-flight spectrometer, which guarantees a maximum collection efficiency. Femtosecond laser pulses are generated by a seeded regenerative Ti:Sa amplifier, which is externally pumped with the second harmonic of a diode-pumped solid-state Nd:YAG laser. A retroreflector mounted on a computer-controlled translation stage serves as a reproducible time delay of the probe pulse. The high energy output of the laser pulses (∼3 mJ) in combination with the variable repetition rate and the high stability of the amplified pulses provide excellent conditions for recording pump-probe photo-electron spectra of mass-separated cluster anions even at the fairly low ion density of pulsed plasma cluster sources. First results on the electron dynamics of the Pt3 - cluster demonstrate the reliability of the whole system. Further experimental investigations will concentrate on electron-relaxation processes in transition- and noble-metal clusters as well as on the nuclear and transition-state dynamics of chemically reacted adsorbate clusters.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s003400000403
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