Decay dynamics of photoexcited alkali chemisorbates: Real-time investigations in the femtosecond regime

Bauer, Michael; Pawlik, S.; Aeschlimann, Martin

doi:10.1103/physrevb.60.5016

Cited by 125 publications

(92 citation statements)

References 47 publications

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“…A theoretical study, together with a comparison of the available experimental data, of the lifetime of electronically excited states in the Na, K, Rb, Cs/Cu(1 1 1) systems has been made by Borisov et al [328]. The theoretical lifetimes of the excited states are found to increase along the sequence Na, K, Rb, Cs in agreement with the experimental results [281][282][283]288]. This evolution along the alkali series is attributed to the alkali polarizabilities.…”

Section: Adsorbate States: Alkali Metalssupporting

confidence: 69%

“…1). The inelastic channel gives similar contributions in both cases leading to values of lifetimes that are in reasonable agreement with the experimental values [281][282][283][284]287]. A theoretical study, together with a comparison of the available experimental data, of the lifetime of electronically excited states in the Na, K, Rb, Cs/Cu(1 1 1) systems has been made by Borisov et al [328].…”

Section: Adsorbate States: Alkali Metalssupporting

confidence: 54%

“…Nevertheless, for the decay time of the 2p Ã resonance in CO/Cu(1 1 1) only an upper limit of 5 fs could be given [280]. Longer lifetimes have been observed for the antibonding s-p-state of alkali atoms [281][282][283][284][285]. In particular, for Cs/Cu (1 1 1), lifetimes between 10 and 50 fs, depending on temperature have been reported [281,283] (see Fig.…”

Section: Adsorbate Statesmentioning

confidence: 99%

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Decay of electronic excitations at metal surfaces

Echenique

Berndt

Chulkov

et al. 2004

Surface Science Reports

438

403

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Section: Adsorbate States: Alkali Metalssupporting

confidence: 69%

Section: Adsorbate States: Alkali Metalssupporting

confidence: 54%

Section: Adsorbate Statesmentioning

confidence: 99%

See 1 more Smart Citation

Decay of electronic excitations at metal surfaces

Echenique

Berndt

Chulkov

et al. 2004

Surface Science Reports

438

403

View full text Add to dashboard Cite

“…], agree in identifying a resonance above the Fermi level as due to the adsorbate electronic state. 36,37,40,60,61 The atomic character of such a feature is confirmed by its coverage-dependent binding energy 35 and by its dispersion-less behavior in k for very low coverages. 36 Due to its symmetry, i.e., its largest intensity for emission normal to the surface, this resonance has been identified as σ (m = 0).…”

Section: Resultsmentioning

confidence: 74%

“…The experiments show that the realistic electronic properties differ substantially from those obtained on jellium, revealing unoccupied and extremely narrow atomic resonances. [35][36][37][38][39][40][41][42][43] Recently, a phenomenological model has shown that for a good description of the electronic properties of the alkali adatom systems is crucial to account for the main characteristics of the electronic properties of the substrate. 44,45 Nevertheless, such a model is also based on the assumption of a complete ionization of the adatom.…”

Section: Introductionmentioning

confidence: 99%

Self-consistent approach for spectral properties of single alkali adatoms on Cu(111)

2012

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We investigate the nature of the adatom-surface interaction in the adsorption of alkali atoms on Cu(111). Our calculation, exploiting the embedding approach in a density functional theory framework, describes an isolated atom on a metallic surface, which is modeled via a one-dimensional modulated potential. The absence of empirical term in the Hamiltonian guaranties a completely ab initio determination of the electronic properties of the system. The role of the projected energy gap in determining lifetime and binding energy of the adatom resonances is evidenced. On the basis of the electronic properties of the adsorbed alkali atoms the covalent/ionic nature of the bonding with the surface is analyzed.

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Time‐resolved two‐photon photoemission

Fauster¹

2003

Solid‐State Photoemission and Related Methods

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In this chapter time resolution will be introduced to photoemission experiments. This means not just a series of regular photoemission measurements to monitor the changes of a sample with time. In two-photon photoemission the time delay between the two photons is an additional experimental parameter which can be controlled with femtosecond resolution, i.e., on a time scale relevant for electronic processes. At the same time, the introduction of the second photon leads to the participation of an additional electronic state in the energy diagram for photoemission. Energy diagramIn Figure 8.1 the transition from initial state |1 to an intermediate state |2 after the absorption of the photon with energy hν a is shown. The second photon of energy hν b excites the electron out of the intermediate state into the final state |3 . If the final state energy E 3 is above the vacuum energy E vac , the electron might leave the surface and its kinetic energy E kin is measured with an electron energy analyzer. Obviously, the initial state has to be occupied, i.e., its energy E 1 should be below the Fermi energy E F . The intermediate state on the other hand has to be empty at first. In most cases it is desirable to keep the photon energy hν a below the work function Φ = E vac − E F , because this constitutes the threshold for one-photon photoemission. This applies also to the other photon, because processes with the role of the two photons interchanged are possible as well. Energy-resolved spectroscopyThe spectrum sketched at the right of Fig. 8.1 shows a peak at the final state energy E 3 . The cutoff at kinetic energy zero corresponds to the vacuum level E vac of the sample. Electrons with the highest energy after the absorption of the photons with energies hν a and hν b appear at kinetic energy E max − E vac = hν a + hν b − Φ. These limits are familiar from regular photoemission spectroscopy and can be used to determine the work function from the width of the spectrum. Similarly, the momentum k of the electron parallel to the surface is conserved for single-crystal surfaces. For electrons emitted at an angle ϑ with respect to the surface normal one obtainshk = √ 2mE kin sin ϑ. Umklapp processes would add reciprocal lattice vectors of the surface to the momentum conservation, but play usually no role in twophoton photoemission. One has to keep in mind that the kinetic energies are generally quite

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Decay dynamics of photoexcited alkali chemisorbates: Real-time investigations in the femtosecond regime

Cited by 125 publications

References 47 publications

Decay of electronic excitations at metal surfaces

Decay of electronic excitations at metal surfaces

Self-consistent approach for spectral properties of single alkali adatoms on Cu(111)

Time‐resolved two‐photon photoemission

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