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191.
Laser‐pump/X‐ray‐probe experiments with electrons ejected from a Cu(111) target: space‐charge acceleration
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G. Schiwietz D. Kühn A. Föhlisch K. Holldack T. Kachel N. Pontius 《Journal of synchrotron radiation》2016,23(5):1158-1170
A comprehensive investigation of the emission characteristics for electrons induced by X‐rays of a few hundred eV at grazing‐incidence angles on an atomically clean Cu(111) sample during laser excitation is presented. Electron energy spectra due to intense infrared laser irradiation are investigated at the BESSY II slicing facility. Furthermore, the influence of the corresponding high degree of target excitation (high peak current of photoemission) on the properties of Auger and photoelectrons liberated by a probe X‐ray beam is investigated in time‐resolved pump and probe measurements. Strong electron energy shifts have been found and assigned to space‐charge acceleration. The variation of the shift with laser power and electron energy is investigated and discussed on the basis of experimental as well as new theoretical results. 相似文献
192.
To investigate the molecular interaction study between secondary amine with aryl and alkyl ether, we report densities, speeds of sound, viscosities and refractive indices of N-ethylaniline (NEA) with aryl (anisole, phenetole) and alkyl (tert-butyl methyl ether) ether over the entire composition regime and in the temperature range of 293.15–323.15 K at 5 K intervals. Various excess and transport properties were derived from the experimental data and the excess parameters were fitted to the Redlich–Kister polynomial equation using multiparametric non-linear regression analysis to derive the binary coefficients and to estimate the standard deviation. Molecular interactions between the unlike molecules were analysed through dipole–dipole interactions, cross-association between the components of the mixtures and H-bond formation. Viscosity and refractive index of the mixtures were predicted through several empirical equations and compared with the experimental results. Prigogine–Flory–Patterson statistical theory was used to predict the excess molar volume results. 相似文献
193.
Inside Cover: A Non‐Exploding Alkali Metal Drop on Water: From Blue Solvated Electrons to Bursting Molten Hydroxide (Angew. Chem. Int. Ed. 42/2016)
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194.
M. Sc. Sebastian Hartweg Dr. Adam H. C. West Dr. Bruce L. Yoder Prof. Dr. Ruth Signorell 《Angewandte Chemie (International ed. in English)》2016,55(40):12347-12350
The famous nonmetal‐to‐metal transition in Na–ammonia solutions is investigated in nanoscale solution droplets by photoelectron spectroscopy. In agreement with the bulk solutions, a strong indication for a transition to the metallic state is found at an average metal concentration of 8.8±2.2 mole%. The smallest entity for the phase transition to be observed consists of approximately 100–200 solvent molecules. The quantification of this critical entity size is a stepping stone toward a deeper understanding of these quantum–classical solutions through direct modeling at the molecular level. 相似文献
195.
196.
以罗通定为手性溶解剂,用核磁共振方法分析了几种小消旋羧酸。考察了化学计量比和浓度对化学位移不等价(△δ)的影响,并比较了在溶剂CDCl3或C6D6中,作为羧酸用手性溶解剂罗通定和(S)-(-)-α-苯乙胺的效果。 相似文献
197.
X. G. Feng Dragana Popovi S. Washburn V. Dobrosavljevi 《Physica E: Low-dimensional Systems and Nanostructures》2000,6(1-4)
We report the discovery of a new and unexpected kind of metal in two dimensions (2D), which exists in the presence of scattering by local magnetic moments. The experiment was carried out on a 2D electron system in silicon, where the local magnetic moments have been induced by disorder and their number was varied using substrate bias (Vsub). In the new metal, the conductivity decreases as σ(ns,T)=σ(ns,T=0)+A(ns)T2 (ns – carrier density) to a non-zero value as temperature T→0. In three dimensions, this T2 dependence is well known, and results from Kondo scattering by local magnetic moments. In 2D, however, the existence of a metal with dσ/dT>0 is very surprising. As the number of local moments is reduced, the range of temperatures [T<Tm(Vsub)] where they dominate transport becomes smaller. For T>Tm, we observe the usual 2D metallic behavior with dσ/dT<0. 相似文献
198.
提出了逐级取样分子模拟方法。通过逐个改变粒子的类别实现在一次模拟中对混合物整个组成范围的取样,并提出适当的处理方法可以同时获取混合物在整个组成范围内的多种超额热力学性质。用本文方法在零压、115.8K下对氩-氪体系作了模拟计算,与McDonald采用常规NPTMonteCarlo模拟结果的比较表明,本文的逐级取样模拟方法是可靠而有效的。 相似文献
199.
V. Žigman 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》1999,7(1):11-16
The results of the evaluation of the viscosity cross-section for elastic electron-xenon collisions, taking into account the
spin-orbit interaction of the continuum electron, in the energy interval from 0.1 eV to 50 eV are presented and discussed.
The calculations are performed on the basis of three theoretically derived sets of phase shift data obtained by different
authors and on the deduced relativistic expression for the viscosity cross-section in terms of phase shifts discerning the
spin-up and spin-down states of the scattered electrons. Comparison with viscosity cross-sections, as evaluated from non-relativistic
phase shifts extracted from experiments, strongly favours the relativistic results. The assumption of isotropic scattering
is critically examined and the error induced by its use is shown to persist to the same extent as in non-relativistic calculations,
at least in the energy region considered.
Received: 22 April 1998 / Received in final form: 16 December 1998 相似文献
200.
Mohammad El-Said 《理论物理通讯》1999,31(3):321-326
The spectra of two-electron quantum dot in a magnetic field of arbitrary strength is studied by using the shifted 1/N expansion method. The comparisons show that our results are in good agreement with the results of fixed-phase quantum Monte Carlo method and exact ones [Bolton, Phys. Rev. B54 (1996) 47801. 相似文献