Book of Abstracts Book of Abstracts - Universität Konstanz

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Femtosecond photoelectron spectroscopy of sodium clusters Abdollah Malakzadeh, Christian Hock, Christof Bartels, Raphael Kuhnen and Bernd v. Issendorff Fakultät für Physik, Universität Freiburg, H.Herderstr. 3, 79104 Freiburg, Germany B - 29 Recently we have shown that the electron gas in a free sodium cluster can be heated by a single fs-laser pulse to temperatures high enough for thermal electron emission to occur [1,2]. This emission can be described by a simple model: the laser excites the collective motion of the electrons (the plasmon), which after a very short time (a few fs) decays into single electron-hole excitations. Due to the strong electron-electron interaction within a short time this nonthermal energy distribution of the electrons is transformed into a thermal one. The electron gas then cools by electron-phonon coupling. Time-resolved pump-probe photoelectron and photofragmentation spectroscopy has been applied to measure the electron-phonon-coupling constant as a function of cluster size. This has been done using relatively long laser pulses (τ ≈ 200 fs). In order to obtain more information about the early stages of the excitation, shorter laser pulses are necessary. Therefore a NOPA (noncolinear optical parametric amplifier) has been constructed, which allows the production of wavelength tunable, short (τ < 50 fs) laser pulses, as well as a hollow capillary compressor. The performance of these devices and first results for sodium clusters are discussed. References [1] R.Schlipper, R. Kusche, B.v.Issendorff and H.Haberland, App. Phys. A. 72, 255 (2001) [2] M.Maier, M. Astruc Hoffmann, and B.v. Issendorff, NJP 5, 3 (2003) 69
B - 30 70 Photoelectron Spectroscopy on Small, Size Selected, Neutral Silver Clusters Embedded in Helium Droplets Andreas Przystawik, Paul Radcliffe, Josef Tiggesbäumker, Karl-Heinz Meiwes-Broer Institut für Physik, Universität Rostock, Universitätsplatz 3, 18051 Rostock, Germany Experiments on neutral clusters are often hampered by a broad distribution of cluster sizes. Therefore most of the work concerning the electronic structure of clusters is performed with charged particles, where one can prepare a molecular beam of species with a certain number of atoms. We present a possibility to exploit absorption resonances to select a cluster size for excitation and ionization from the neutral beam. This technique is used to record two-photon photoelectron spectra of small silver clusters grown in helium nanodroplets by the pickup method. We derive information on both, the cluster and its electronic structure, and the interaction with the helium environment. An analysis of the spectra recorded at different wavelengths shows that all investigated systems undergo a rapid relaxation on a picosecond timescale to the lower edge of the broad excitation, see figure 1. One possibility of helium pickup sources is to prepare clusters in high spin states as already demonstrated with alkali clusters on the surface of droplets [1]. Despite the lack of selectivity in favor of high spin states when growing the clusters inside the droplet we can clearly detect silver dimers in triplet states not present in gas phase spectroscopy. Figure 1. Schematic diagram of the ionization dynamics of Ag 8 [2]. After excitation to the unoccupied band E * roughly 4.0 eV above the ground state, the cluster quickly relaxes to the lower edge EL. In a R2PI experiment, ionization occurs from this long-living level. References [1] P. Claas, D. Schumacher, and F. Stienkemeier, Phys. Rev. Lett. 92, 013401 (2004). [2] P. Radcliffe et al., Phys. Rev. Lett. 92, 173403 (2004).
Page 1 and 2:
Symposium on Size Selected Clusters
Page 4:
Table of Contents FULL LENGTH TALKS
Page 8 and 9:
Metallic clusters and oxygen Cather
Page 10 and 11:
Infrared Spectroscopy of Metal Ion
Page 12 and 13:
Model Gold Catalysts by Size-Select
Page 14 and 15:
Ultra-stable Hetero-nuclear Microcl
Page 16 and 17:
Tailoring functionality of clusters
Page 18 and 19:
The hydrogen transfer reaction: fro
Page 20 and 21:
Atomic and Molecular Architecture a
Page 22 and 23:
Magnetic Properties of Deposited Tr
Page 24 and 25: Cluster ferroelectricity Walt de He
Page 26 and 27: Oxidation Effects of the Small Chro
Page 28 and 29: Electronic structure and bonding in
Page 30 and 31: Catalytic CO oxidation on ionic pla
Page 32 and 33: Melting, Pre-melting, and Glass Tra
Page 34 and 35: Vibrational Spectroscopy of Large S
Page 36 and 37: Novel Properties of Soft-Nano-Molec
Page 38: Posters 33
Page 42 and 43: Structure and Bonding in Carbon Clu
Page 44 and 45: Photoelectron Spectroscopy of Fulle
Page 46 and 47: Nucleation of single-walled carbon
Page 48: Chemistry 43
Page 51 and 52: 46 B - 8 Triplatinum carbonyl compl
Page 53 and 54: B - 10 48 Structural and Electronic
Page 55 and 56: B - 12 50 Size Dependent Carbon Mon
Page 57 and 58: B - 14 52 Binding energies of CO an
Page 59 and 60: B - 16 54 Reactivity of Size-Select
Page 61 and 62: B - 18 56 Oxygen adsorption at anio
Page 63 and 64: B - 20 Gold Clusters, CO-Chemisorbe
Page 65 and 66: B - 22 60 Probing the Electronic St
Page 67 and 68: B - 24 62 Joint theoretical and exp
Page 70 and 71: Photoionization Dynamics of Pure He
Page 72 and 73: Fast Electronic Relaxation in Metal
Page 76 and 77: Signatures of the Giant Dipole Reso
Page 78 and 79: Embedding of Na clusters in raregas
Page 80 and 81: Theoretical studies of ultrafast pr
Page 82: Magnetism 77
Page 85 and 86: B - 38 80 Mn clusters: a nanoscale
Page 88 and 89: Materials 83
Page 90 and 91: Intensity 10000 8000 6000 4000 2000
Page 92 and 93: Passivation, charging and optical p
Page 94: WS and MoS: Magic Clusters and Nano
Page 98 and 99: PEACE - a new photoelectron action
Page 100 and 101: B - 47 Computational Electron Spect
Page 102 and 103: Photoionisation using Kohn-Sham wav
Page 104: Structural characterization of larg
Page 107 and 108: A - 0 102
Page 109 and 110: A - 2 104 Gold Clusters with Densit
Page 111 and 112: A - 4 Structure Determination of Sm
Page 113 and 114: A - 6 108 Mass Spectrometric Invest
Page 115 and 116: A - 8 110 Probing the properties of
Page 117 and 118: A - 10 112 Planar Boron Clusters an
Page 119 and 120: A - 10 114
Page 121 and 122: A - 12 116 Infrared Spectroscopy of
Page 123 and 124: A - 14 118 Computational Study of (
Page 126 and 127:
Phase Transitions 121
Page 128 and 129:
Structural changes in small and med
Page 130 and 131:
Molecular Dynamics Simulations of t
Page 132 and 133:
Rare Gases 127
Page 134 and 135:
A - 20 Decay behaviour of dimer ion
Page 136 and 137:
High resolution electron ionization
Page 138:
Photodissociation of rare-gas trime
Page 141 and 142:
A - 24 136
Page 143 and 144:
A - 26 138 Sizedependence of Electr
Page 146 and 147:
Solvations 141
Page 148 and 149:
Ionization Potentials of Large Sodi
Page 150:
First principles studies on the rea
Page 153 and 154:
148
Page 155 and 156:
A - 32 150 Single Atom Dispersion o
Page 157 and 158:
A - 34 152 Supported Gold Clusters
Page 159 and 160:
A - 36 The Size-Evolution of the Op
Page 161 and 162:
A - 38 156 Transition From One- to
Page 163 and 164:
A - 40 158 Multiple Size-Selected C
Page 165 and 166:
A - 42 160 A comparative simulation
Page 167 and 168:
A - 44 DFT-Investigations of coales
Page 169 and 170:
A - 46 164 Mass-selected Nanocrysta
Page 172 and 173:
Author Index 167
Page 174 and 175:
Abbet, S...........................
Page 176 and 177:
Murakami, J........................
Page 178:
Time 8.30 a.m. 9.15 a.m. 10.00 a.m.
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Book of Abstracts Book of Abstracts - Universität Konstanz

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