Photoinduced plasmon excitations in alkali-metal overlayers
نویسندگان
چکیده
Collective surface excitations in alkali-metal overlayers are observed using photoyield spectroscopy. Spectra for Na and K on Al~111! reveal a multipole surface plasmon and bulklike overlayer plasmon. In contrast, Li on Al exhibits only the multipole mode. In the submonolayer regime, all three alkali metals provide evidence for the threshold excitation. Time-dependent density-functional calculations for realistic alkali-metal overlayers agree well with these observations. @S0163-1829~98!07408-6#
منابع مشابه
How harmonic is dipole resonance of metal clusters?
We discuss the degree of anharmonicity of dipole plasmon resonances in metal clusters. We employ the time-dependent variational principle and show that the relative shift of the second phonon scales as N−4/3 in energy, N being the number of particles. This scaling property coincides with that for nuclear giant resonances. Contrary to the previous study based on the boson-expansion method, the d...
متن کاملElectronic promoters and semiconductor oxidation: Alkali metals on Si(111) surfaces.
We examine the effect of thin (1-2 monolayers) overlayers of the lowelectronegativity Cs and Na metals on the oxidation of Si(111) cleavage surfaces. Synchrotron radiation photoemission studies of oxygen chemisorption as a function of overlayer thickness and oxygen exposure indicate large oxidation promotion effects and the formation of Si-oxide phases where high Si-oxidation states dominate. C...
متن کاملQuantum plasmonics: Symmetry-dependent plasmon-molecule coupling and quantized photoconductances
We investigate photoinduced electron transport through nanoparticle dimers connected by linear and ringlike molecules. The two model junctions exhibit similar absorption but distinct photoconductance. The linear-chain junction shows a constant conductance that is independent of photon energies. In contrast, the ring molecules show quantized conductance resonances at energies corresponding to th...
متن کاملTunability by alkali metal cations of photoinduced charge separation in azacrown functionalized graphene.
A modified graphene oxide containing aza-9-crown-3 ether units covalently anchored has been prepared; aqueous suspensions of this material in the presence of Li(+), Na(+) and K(+) cations exhibit enhanced electrochemical response, enhanced photoinduced charge separation and longer lifetimes, facts that can be attributed to stabilization of electrons on graphene oxide by the nearby alkali metal ...
متن کاملAb Initio Evaluation of Plasmon Lifetimes in the Alkali Metals
The anomalous plasmon linewidth dispersion (PLD) measured in K by vom Felde, Sprösser-Prou, and Fink (Phys. Rev. B 40, 10181 (1989)), has been attributed to strong dynamical electron-electron correlations. On the basis of ab initio response calculations, and detailed comparison with experiment, we show that the PLD of K is, in fact, dominated by decay into particle-hole excitations involving em...
متن کامل