1. Ultrafast relaxation of photoexcited superfluid He nanodropletsM. Mudrich, A.C. LaForge, A. Ciavardini, P. O'Keeffe, C. Callegari, M. Coreno, A. Demidovich, M. Devetta, M. Di Fraia, M. Drabbels, P. Finetti, O. Gessner, C. Grazioli, A. Hernando, D.M. Neumark, Y. Ovcharenko, P. Piseri, O. Plekan, K.C. Prince, R. Richter, M.P. Ziemkiewicz, T. Moller, J. Eloranta, M. Pi, M. Barranco, F. Stienkemeier, 2020, izvirni znanstveni članek Ključne besede: helium, helium nanodroplet, nanomaterial, density functional theory, dipole, excitation, ionization, photoelectron spectroscopy, photoexcitation, photon, simulation, ultraviolet radiation, ultrafast photoemission, free electron laser, ultrafast spectrscopy
Objavljeno v RUNG: 20.01.2022; Ogledov: 1007; Prenosov: 0
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2. Photoexcitation processes in atomsAlojz Kodre, Iztok Arčon, Jana Padežnik Gomilšek, 2021, samostojni znanstveni sestavek ali poglavje v monografski publikaciji Opis: Photoelectric absorption is characterized by a smooth power-law decrease of the
cross section with photon energy. Absorption edges reveal rich structure, which
continues into the high-energy side. The quasiperiodic signal, superposed onto
the smooth basis, due to scattering of the photoelectron on the neighbours of the
target atom provides the basis for the structural (XAFS) analysis of the material.
Irregular tiny resonances and edges that appear over the same general range as
XAFS are recognized as intra-atomic effects: multielectron excitations (MEE)
owing to correlated motion in the electronic cloud. The systematic study of MEE
began on noble gases and metallic vapours, both of which are gases of free
atoms. With some extremely strong MEE, mostly coexcitations of the subvalence
d and f electrons, the structural XAFS analysis may be compromised;
hence, there is a need to independently determine the MEE signal, the atomic
absorption background (AAB) for the analyzed element, and remove it prior to
analysis. In view of the scarcity of elements which can practically be prepared in
a free-atom gas state, several approaches to approximate the AAB have been
developed: analysis of disordered compounds, where the weak and simple
XAFS signal can be modelled and removed, and correlation analysis of the
absorption spectra of several independent samples, where the AAB is extracted
in an iterative procedure.
Ključne besede: photoexcitation, XAFS, multielectron excitations, atomic
absorption background
Objavljeno v RUNG: 15.12.2021; Ogledov: 1032; Prenosov: 0
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3. Evidence of enhanced photocurrent response in corannulene filmsNadya Patukhova, Layla Martin Samos, Egona Pavlica, Gvido Bratina, 2017, izvirni znanstveni članek Opis: Photoconductivity spectra measured in non-crystalline corannulene thin layers are compared to optical absorption in solution phase and thin films. The unexpected enhanced photoconductivity is correlated with GW–BSE theoretical predictions of corannulene gas-phase excitonic spectra. Theoretical analysis reveals a consistent contribution involving transitions to Super Atomic Molecular Orbitals (SAMOs), a unique set of diffuse orbitals typical of curved conjugated constructs. Results suggest SAMO population via direct photoexcitation as a potential mechanism towards exploiting these diffuse orbitals as conducting channels in suitably assembled quantum nanostructures or solids.
Ključne besede: Coranulene, photoconductivity, thin layers, photoexcitation
Objavljeno v RUNG: 26.09.2017; Ogledov: 3212; Prenosov: 198
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