4,017 research outputs found
Electron transfer with core-level excitations at hybrid interfaces
No full textElectron core-level spectroscopies have emerged as effective tools to investigate several aspects of the hybrid interface between organic molecules and a substrate. In particular, resonant photoemission spectroscopy can measure interfacial electron transfer times down to the femtosecond timescale. Furthermore, the strong perturbation induced by the core hole opens up the several questions on how the properties of the interface are modified, calling for a theoretical description of the core-excited system.
We adopt a theoretical framework based on density-functional theory (DFT), where the excitation is introduced explicitly in the core-level occupation of an atom in a molecule, to investigate the electronic structure and electron transfer from/to organic molecules adsorbed on metal, semimetal, and semiconducting substrates.
The perturbing potential lowers the energy of the molecular orbitals. Focusing on the lowest-unoccupied (LUMO), a filling of the core-excited LUMO* by substrate electrons may occur within the core-hole lifetime, as found for molecules on metals where the adsorption angle is also shown to influence the electron transfer rate [1,2]. In the case of a semimetal graphene substrate, a spin-polarized LUMO* pinned at the Fermi level can be determined for physisorbed molecules. In that case electron transfer would be suppressed given the low density of states of unsupported graphene at that energy, but still possible for graphene supported on a metal [3]. For molecules adsorbed on a semiconductor, the LUMO* may form a bound exciton in the gap [4]. Here, we found especially interesting to consider the influence of thermal motion on the energy-level alignment and the absorption coefficient [5,6].
References
[1] D. Cvetko, G. Fratesi, G. Kladnik, A. Cossaro, G.P. Brivio, L. Venkataraman, and A. Morgante, submitted.
[2] A. Baby, G. Fratesi, S.R. Vaidya, L.L. Patera, C. Africh, L. Floreano, G.P. Brivio, J. Phys. Chem. C 119 (2015) 3624.
[3] A. Ravikumar, A. Baby, H. Lin, G.P. Brivio, and G. Fratesi, Scientific Reports 6 (2016) 24603.
[4] G. Fratesi, C. Motta, M. I. Trioni, G. P. Brivio, and D. Sánchez-Portal, J. Phys. Chem. C 118 (2014) 8775
[5] H. Lin, G. Fratesi, S. Selçuk, G.P. Brivio, and A. Selloni, J. Phys. Chem. C, 120 (2016) 3899.
[6] M. Muller, D. Sànchez-Portal, H. Lin, G. Fratesi, G.P. Brivio, and A. Selloni, in preparation
Electron transport through single donors in silicon
No full text-Kavli Institute of Nanoscience DelftApplied Science
Effect of Film Thickness on Magnetic Properties of FePt Thin Films Deposited on Amorphous SiO2 Substrate Directly
No full textThe study of magnetic properties and microstructures of nano-size FePt islands on amorphous carbon film
No full text
New (Probabilistic) Derivation of Diaz-Metcalf and Pólya-Szegő Inequalities and Consequences
No full textClassical inequalities of Diaz - Metcalf and Pólya - Szegő are generalized to
probabilistic setting which covers the initial deterministic (both discrete and integral) variants.
From these two inequalities, by the probabilistic derivation method further well -
known inequalities are obtained (that ones by Kantorovich, Rennie and Schweitzer)
The electrons are waves: impossible interview to C.J. Davisson (1881-1958) and G.P. Thomson (1892-1975)
No full textThe author imagines to interview the Nobel Laureates in Physics of the year 1937, who turned upside-down modern physics, demonstrating the wave nature of matter. The answers of C. Davisson and G.P. Thomson are based on
the Nobel Lectures they delivered during the Nobel Prize Award Ceremony
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