X-ray magnetic circular dichroism at IrL2,3 edges in Fe100−x Ir x and Co100−x Ir x alloys: Magnetism of 5d electronic states

The formation of induced 5d magnetic moment on Ir in Fe_100−x Ir _x (x=3, 10 and 17) and Co_100−x Ir _x (x=5, 17, 25 and 32) alloys has been investigated by X-ray magnetic circular dichroism (XMCD) at Ir L_2,3 absorption edges. Sum rule analysis of the XMCD data show that the orbital moment of Ir is in the range of −0.071(2)μB to −0.030(1)μB in Fe-Ir alloys and −0.067(2)μB to 0.024(1)μB in Co-Ir alloys. We find that the total moment of Ir in Fe-Ir alloys is approximately 1/5 of the total 3d moment on Fe at all the three compositions. In contrast, the total moment on Ir in Co-Ir alloys varies between 1/6 to 1/16 of the 3d moment on cobalt. The observed trends of Ir moments and the role of interatomic exchange interactions in 5d moment formation are discussed.     

Exploiting stored TiO2 electrons for multi-electron reduction of an azo dye methyl orange in aqueous suspension

The mechanism of multi-electron reduction of methyl orange (MO) azo dye on TiO₂ nanoparticles has been studied performing stopped flow technique. A multi-electron reduction of azo dye has been investigated. It was found that a multistep reduction of the dye takes place: the stored electrons reduce the conjugative system of the azo group resulting in the decolorization of the dye and leading to the formation of hydrazine derivative followed by further 2 electron transfer step leading to the cleavage of the N–N bond and the formation of aromatic amines. The FTIR analysis of the products confirms the proposed mechanism of the dye reduction. The kinetic parameters and of the multi-electrons reduction of the MO have been determined. The rate of MO reduction was found to be dependent on both the TiO₂ electrons and the dye concentrations.     

Hot Electrons at Solid–Liquid Interfaces: A Large Chemoelectric Effect during the Catalytic Decomposition of Hydrogen Peroxide

The study of energy and charge transfer during chemical reactions on metals is of great importance for understanding the phenomena involved in heterogeneous catalysis. Despite extensive studies, very little is known about the nature of hot electrons generated at solid–liquid interfaces. Herein, we report remarkable results showing the detection of hot electrons as a chemicurrent generated at the solid–liquid interface during decomposition of hydrogen peroxide (H₂O₂) catalyzed on Schottky nanodiodes. The chemicurrent reflects the activity of the catalytic reaction and the state of the catalyst in real time. We show that the chemicurrent yield can reach values up to 10^?1 electrons/O₂ molecule, which is notably higher than that for solid–gas reactions on similar nanodiodes.     

Surface chemistry of hot electron and metal-oxide interfaces

Fundamental mechanisms for energy conversion and dissipation on surfaces and at interfaces have been significant issues in the community of surface science. Electronic excitation in exothermic chemical reactions or photon absorption involves the generation of energetic or hot electrons that are not in thermal equilibrium via non-adiabatic electronic excitation. A number of experimental and theoretical studies have demonstrated the influence of excited hot electrons on atomic and molecular processes, and it is a key moderator in the surface energy conversion process. The charge transfer through the metal-oxide interfaces has a significant impact on catalytic performance in mixed metal-oxide catalysts. In order to understand the influence of hot electrons and metal-oxide interfaces on the surface reactions, various detection schemes of exoelectron detection, including metal-insulator-metal and metal-semiconductor Schottky diodes, have been developed. Catalysts coupled with surface plasmons exhibit peculiar catalytic performance related to hot electron flow. In this review, we outline recent research efforts to relate hot electron flow with surface reactions occurring at metal-oxide interfaces. We report recent studies on the observation of hot electrons and the correlation between hot electrons and catalytic activity and selectivity on metallic surfaces. We show recent results from studies of surface reactions on nanocatalysts coupled with surface plasmons, where hot electron transport is the key process in energy dissipation and conversion processes.     

N(O)的分布与原子核外电子的分布、V与电离势的关联

BCS超导电性微观理论中提出超导材料的超导转变温度Tc由θ(临近费米界面电子之间的相互吸引),λeff=N(O)V(N(O)在费米界面每单位能量的一种自旋Bloch态密度;V=平均,电子对在-ω<ε<ω在区域中跃迁的矩阵元Vkk′能为衡量的平均矩阵元)决定,并给出计算公式.基于高Tc超导材料的特征,用电负性均衡原理分析了由于在高Tc超导材料中的元素有化学键的形成,N(O)和V具有特殊的变化,电声子机制可以产生高Tc超导电性。     

Analysis of a 14-mev neutron scattering experiment with Li2O

Analysis was performed for neutron leakage spectrum measurements with Li₂O assemblies to test the adequacy of ENDF/B-V data. Significant differences between calculated and measured results are observed.     

Detectivity dependence of quantum dot infrared photodetectors on temperature

The detectivity of Quantum dot infrared photodetectors (QDIPs) has always attracted a lot attention as a very important performance parameter. In the paper, based on the theoretical model for the detectivity with the consideration of the common influence of the microscale electron transport, the nanoscale electron transport and the self-consistent potential distribution of the electrons, the dependence of the detectivity of the QDIP on temperature is discussed by analyzing the influence of the temperature on the average electrons number in a quantum dot. Specifically, the average electrons number in a quantum dot shows different change trends (from the increase to decrease) with the increase of the temperature, but the detectivity presents the single decrease trend with the temperature, which can provide the designers with the theoretical guidance for the performance optimization of the QDIP devices.