Electronic states cluster-trapped

Since solids do not exist as truly infinite systems, there are issues related to their temiination (i.e. surfaces). However, in most cases, the existence of a surface does not strongly affect the properties of the crystal as a whole. The number of atoms in the interior of a cluster scale as the cube of the size of the specimen while the number of surface atoms scale as the square of the size of the specimen. For a sample of macroscopic size, the number of interior atoms vastly exceeds the number of atoms at the surface. On the other hand, there are interesting properties of the surface of condensed matter systems that have no analogue in atomic or molecular systems. For example, electronic states can exist that trap electrons at the interface between a solid and the vacuum [1]. 

Figure 1.4 shows the DOS for the sum of 3s, 3p and 3d components of the magnesium atom located at a center of the cluster model of Zn18Mg. Also, the DOS is shown in Figure 1.4 for the sum of 3d, 4s and 4p components of the zinc atom located at a center of the cluster model of Zn19. From the DOS for Zn, the strong localization of the 3d component was found as peak "a" shown in Figure 1.4. Peaks A and A in the DOS for Mg corresponded to the trapped state of electrons by the 3d component of Zn. Also, the peaks B-G in the DOS for Mg are overlapped with the peaks b-g in the DOS for Zn. Namely, the electronic state DOS for Mg localized by the presence of Zn in the neighborhood, resulting in the deviation from the free-electron parabolic law. It is likely that such electronic states for the...

In this chapter, the recent progress in the understanding of the nature and dynamics of excess (solvated) electrons in molecular fluids composed of polar molecules with no electron affinity (EA), such as liquid water (hydrated electron, and aliphatic alcohols, is examined. Our group has recently reviewed the literature on solvated electron in liquefied ammonia and saturated hydrocarbons and we refer the reader to these publications for an introduction to the excess electron states in such liquids. We narrowed this review to bulk neat liquids and (to a much lesser degree) large water anion clusters in the gas phase that serve as useful reference systems for solvated electrons in the bulk. The excess electrons trapped by supramolecular structures (including single macrocycle molecules ), such as clusters of polar molecules and water pools of reverse micelles in nonpolar liquids and complexes of the electrons with cations in concentrated salt solutions, are examined elsewhere. 

To identify these inelastic scattering processes, mass spectra were obtained before and after cluster exposure to the e -beam. Figure 7.4 shows mass spectra of trapped AU55+ clusters before and after e -beam exposure. The primary series of inelastic processes is observed to comprise multiple ionization steps accompanied by sequential losses of single atoms. The rate of this series of inelastic processes was found to increase with increasing cluster size. The fast electron interacts primarily with the electronic states of the cluster and fragmentation arises primarily from a... 

Another positron state is formed when free volume-type crystal defects are present in the metal crystal. The positively charged ionic cores are missing from these defects, so, usually they are effective traps for any positive particle, including the positron in our case. Thus, in most metals, vacancies, vacancy clusters, dislocations, and grain boundaries localize some or all of the free positrons and produce another positron state, the trapped positron. These localized positrons still can meet conducting electrons, but ionic cores are out of their reach. Accordingly, their annihilation characteristics differ from those of free positrons significantly. Different kinds of traps all have their own characteristic annihilation parameters but these parameters are very close to each other. 

Inorganic chemists generally are unhappy with formulations of tin in oxidation state III. The formulation here ought not to be taken too seriously. Disproportionation into Sn(IV) and Sn(II) conceivably may occur. Alternatively, SnlllO(OH) may well correspond to trapping of an electron by a cluster of tin ions. 

In fact, with small particles or clusters, a range of excited state lifetimes could be observed by spectroscopic methods . The observed non-Arrhenius dependence indicated the importance of multiphonon electron tunnelling, probably to preexistent traps. The shorter lifetimes observed at shorter emission wavelenths indicated significant coulombic interaction between traps. 

Attempts have been made to observe and experimentally determine the structure of CH5+ in the gas phase and study it in the condensed state using IR spectroscopy,764 765 pulse electron-beam mass spectrometry,766 and Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS).767 However, an unambiguous structure determination was unsuccessful. Retardation of the degenerate rearrangement was achieved by trapping the ion in clusters with H2, CH4, Ar, or N2. 

In summary, the dynamics of the electronic decay of inner-shell vacancies in a charged environment, such as created by interaction of a cluster with a high intensity FEL radiation, can be qualitatively different from the one induced by a low-intensity source. If the emitted electrons are slow enough to be trapped by the neighboring charges, the familiar exponential decay will be suppressed by quantum beats between the initial state and the quasi-continuum of discrete final states. Physically, the predicted oscillations correspond to creation of the initial vacancy due to the reflections of the emitted electron by the charged cluster potential and the subsequent inverse Auger transition. 

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