Towards Single-Particle Spectroscopy of Small Metal Clusters

Pohl, Andreas; Reinhard, P.‐G.; Suraud, E.

doi:10.1103/physrevlett.84.5090

Cited by 79 publications

(76 citation statements)

References 26 publications

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“…For multi-photon ionization, the relative proportion of double to single ionization for He, while given much better in approximate TDDFT calculations than in previous calculations assuming a sequential mechanism, still does not show the same pronounced features (the 'knee') seen in experiments [110,111]. The electron spectra from above-threshold ionization have recently been calculated within TDDFT [13,112]. Since the ionization yields and above-threshold ionization spectra depend on probabilities extracted directly from the wavefunction, these errors are suspected to be sins of the wavefunction, mentioned above.…”

Section: Where ∆ (Acc)mentioning

confidence: 99%

Time-dependent density functional theory: Past, present, and future

Burke

Werschnik

Gross

2005

The Journal of Chemical Physics

863

586

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Time-dependent density functional theory (TDDFT) is presently enjoying enormous popularity in quantum chemistry, as a useful tool for extracting electronic excited state energies. This article discusses how TDDFT is much broader in scope, and yields predictions for many more properties. We discuss some of the challenges involved in making accurate predictions for these properties.Kohn-Sham density functional theory [1,2,3] is the method of choice to calculate ground-state properties of large molecules, because it replaces the interacting manyelectron problem with an effective single-particle problem that can be solved much faster. Time-dependent density functional theory (TDDFT) applies the same philosophy to time-dependent problems. We replace the complicated many-body time-dependent Schrödinger equation by a set of time-dependent single-particle equations whose orbitals yield the same time-dependent density n(r, t). We can do this because the Runge-Gross theorem [4] proves that, for a given initial wavefunction, particle statistics and interaction, a given time-dependent density n(r, t) can arise from at most one time-dependent external potential v ext (r, t). We define time-dependent Kohn-Sham (TDKS) equations that describe N non-interacting electrons that evolve in v S (r, t), but produce the same n(r, t) as that of the interacting system of interest. Development and applications of TDDFT have enjoyed exponential growth in the last few years [5,6,7,8], and we hope this merry trend will continue.The scheme yields predictions for a huge variety of phenomena, that can largely be classified into three groups: (i) the non-perturbative regime, with systems in laser fields so intense that perturbation theory fails, (ii) the linear (and higher-order) regime, which yields the usual optical response and electronic transitions, and (iii) back to the ground-state, where the fluctuation-dissipation theorem produces ground-state approximations from TDDFT treatments of excitations.In the first, non-perturbative regime, we have systems in intense laser fields with electric field strengths that are comparable to or even exceed the attractive Coulomb field of the nuclei [5]. The time-dependent field cannot be treated perturbatively, and even solving the time-dependent Schrödinger equation for the evolution of two interacting electrons is barely feasible with present-day computer technology [9]. For more electrons in a time-dependent field, wavefunction methods are prohibitive, and in the regime of (not too high) laser intensities, where the electron-electron interaction is still of importance TDDFT is essentially the only practical scheme available. With the recent advent of atto-second laser pulses, the electronic time-scale has become accessible. Theoretical tools to analyze the dynamics of excitation processes on the attosecond time scale will become more and more important. An example of such a tool is the time-dependent electron localization function (TDELF) [10,11]. This quantity allows the time-resolved observation of ...

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Section: Where ∆ (Acc)mentioning

confidence: 99%

Time-dependent density functional theory: Past, present, and future

Burke

Werschnik

Gross

2005

The Journal of Chemical Physics

863

586

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“…The upper panel of Fig. 3 shows the PES for the off-resonant case, which is typical for the cluster ground state [13]. The structures corresponding to single-electron hole states 1d, 1p and 1s are well visible.…”

mentioning

confidence: 97%

“…The PES structures and their satellites are strong and can be well discriminated for intensities I = 2 · 10 10 − 2 · 10 11 W/cm 2 . Smaller intensities result in too weak photoelectron yield while higher intensities lead to considerable broadening the PES (see also [13]). The calculations with the fixed intensity I = 10 11 W/cm 2 (as in Figs.…”

mentioning

confidence: 99%

Two-photon excitation of low-lying electronic quadrupole states in atomic clusters

et al. 2006

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A simple scheme of population and detection of low-lying electronic quadrupole modes in free small deformed metal clusters is proposed. The scheme is analyzed in terms of the TDLDA (timedependent local density approximation) calculations. As test case, the deformed cluster N a + 11 is considered. Long-living quadrupole oscillations are generated via resonant two-photon (two-dipole) excitation and then detected through the appearance of satellites in the photoelectron spectra generated by a probe pulse. Femtosecond pump and probe pulses with intensities I = 2 · 10 10 − 2 · 10 11 W/cm 2 and pulse duration T = 200 − 500 fs are found to be optimal. The modes of interest are dominated by a single electron-hole pair and so their energies, being combined with the photoelectron data for hole states, allow to gather new information about mean-field spectra of valence electrons in the HOMO-LUMO region. Besides, the scheme allows to estimate the lifetime of electron-hole pairs and hence the relaxation time of electronic energy into ionic heat.

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“…This effect was studied for Na clusters in [31] and it was found that the amount of perturbation depends on the strength of the external field. The effect can be quantified in terms of the average number of emitted electrons.…”

Section: Na Clustersmentioning

confidence: 99%

Frequency dependence of level depletion in Na clusters and in C₂H₄

Vidal

Wang

Dinh

et al. 2010

J. Phys. B: At. Mol. Opt. Phys.

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Abstract. In the framework of time-dependent density-functional theory, we study electron emission from Na clusters and the C 2 H 4 molecule as induced by irradiation with an intense pulse. The collision of a charged projectile on C 2 H 4 is also explored for comparison. We look in particular at the level depletion, i.e. the electron loss in each single-electron level separately. It is found that the distribution of electron loss depends sensitively on the photon frequency. Frequencies close to visible light remove electrons exclusively from the vicinity of the Fermi surface while light in the higher UV range (up to 20 eV for Na clusters and up to 136 eV for C 2 H 4 ) depletes all levels about equally strong, down to the deepest bound valence state.Confidential: not for distribution.

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Towards Single-Particle Spectroscopy of Small Metal Clusters

Cited by 79 publications

References 26 publications

Time-dependent density functional theory: Past, present, and future

Time-dependent density functional theory: Past, present, and future

Two-photon excitation of low-lying electronic quadrupole states in atomic clusters

Frequency dependence of level depletion in Na clusters and in C₂H₄

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Towards Single-Particle Spectroscopy of Small Metal Clusters

Cited by 79 publications

References 26 publications

Time-dependent density functional theory: Past, present, and future

Time-dependent density functional theory: Past, present, and future

Two-photon excitation of low-lying electronic quadrupole states in atomic clusters

Frequency dependence of level depletion in Na clusters and in C2H4

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Frequency dependence of level depletion in Na clusters and in C₂H₄