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Evolution of metallic properties of free and initially neutral nanoscale Bi clusters has been studied using synchrotron radiation excited photoelectron spectroscopy. The 4f and 5d core as well as the valence levels have been probed. The cross-level analysis indicates metallic properties in Bi clusters in the observed size range from 0.5 nm to 1.4 nm. The behavior of the core-level and valence binding energies as a function of cluster size has been observed to be smooth and relatively consistent. Valence responses for the largest clusters have their shape and width similar to those of the polycrystalline solid Bi. [ABSTRACT FROM AUTHOR]

Abstract: The 3p 54s 23d 1P1 and 3p 5(2P3/2)4s 25s 2[3/2]1 resonance regions of Ca atoms have been studied experimentally with the aid of synchrotron radiation excited electron spectroscopy. The strong configuration interaction of the 3p 54s 23d, 3p 54s 25s and several other nearly degenerate configurations leads to complex structures observed in the photoelectron yield spectrum. Multiconfiguration Dirac–Fock (MCDF) calculations have been performed for these 3p-excited resonances of neutral calcium and compared to experimental results. The excitation and subsequent autoionization of these resonances lead to the final ionic 3p 6 nl states from which new high-lying members of the Rydberg p-series have been resolved experimentally. These new levels agree reasonably well with calculations as well as with the extrapolation of the Rydberg formula. The post collision interaction (PCI) effect has been observed in the transition Ca+ 3p 53d4s 2P1/2,3/2→ Ca2+ 3p 6 and explained by means of the rather long core-hole lifetime, while the decay of Ca+ 3p 53d4s 4P1/2,3/2,5/2 states is not affected by PCI. [Copyright &y& Elsevier]

Abstract: High resolution 4f photoelectron spectra have been measured from Au, Pb, and Bi vapors using synchrotron radiation. New accurate binding energy values are found to deviate more than 0.3eV for Au from the previous results demonstrating the need for new precise values, e.g. for chemical shift and cluster studies. For Bi both atomic and diatomic lines have been observed simultaneously, molecular lines at 0.96eV lower binding energies. Fine structure splitting created by the coupling of the 4f core hole to the open 6p shell has been found to manifest itself in this high resolution experiment as slightly different line widths for 4f spin components. The fine structure has been investigated also theoretically by calculating the 4f photoionization energies, intensities, and lifetimes using the multiconfigurational Dirac–Fock approach. [Copyright &y& Elsevier]

Neutral Pb clusters in the size range from a few tens of atoms up to ∼100 atoms are studied using synchrotron-based photoelectron spectroscopy. The electronic structure is seen to differ increasingly from that of the solid when the cluster size decreases. The valence band narrows gradually – down to about one fifth of the solid-state band width at the smallest size of few tens of atoms. Simultaneously the Fermi-edge energy shifts further away from the solid value by more than 2 eV. The Pb 5 d core level binding energy also increases and the spectral features broaden and change in shape. The changes observed for the valence and for the 5 d response energies and shapes are discussed in the context of the metal-to-insulator transition observed earlier in Pb clusters below the critical size of 20–30 atoms/cluster. [ABSTRACT FROM AUTHOR]

Abstract: Binding energy shifts between atomic and solid states have been observed with improved accuracy for Au 4f and Ag 3d core levels applying a simultaneous measurement method. Also the 3d photoelectron spectrum and binding energies of free Ag atoms have been observed for the first time. New values determined as free atom to bulk solid shifts deviate considerably from previous estimate for Au but agree reasonably well for Ag. The valence bands were also found to shift rather accurately by the same amount as the core levels. [Copyright &y& Elsevier]

Abstract: Molecular LiCl and Li2Cl2 have been studied in the vapor phase with valence photoelectron and photoelectron–photoion coincidence spectroscopies. These two techniques determine the binding energies in fundamentally different ways. Binding energies obtained from photoelectron spectra are usually taken as the vertical ionization energies of the corresponding electronic states. In cases with several overlapping bands, corresponding to different electronic states, the coincidence measurement can separate the bands if the respective final states fragment differently. This applies well to the monomer case. To facilitate the determination of state-specific ionization energies in the dimeric molecule, a theoretical Franck–Condon analysis has been carried out. Moreover, ab initio coupled-cluster and density-functional-theory calculations have been used to analyze the fragmentation pattern based on asymptotic dissociation energies. The fragmentation pattern is largely common to all the accessible valence-ionized states of the dimer, consistent with rapid conversion to the ionic ground state before fragmentation. However, the highest-lying state of Li2Cl2 +, 2 A g , shows enhanced propensity for Li+ as dissociation product. [Copyright &y& Elsevier]

Abstract: Binding energy shifts between free and solid state atoms for K 2p and Rb 3d photolines have been determined by measuring the vapor and solid state spectra simultaneously in similar experimental conditions applying synchrotron radiation excited photoelectron spectroscopy. This method has the important benefit that the work function is not needed to correct for different reference energy levels, therefore much more accurate values for binding energy shifts are obtained. [Copyright &y& Elsevier]