Electronic Structure of Warm Dense Copper Studied by Ultrafast X-Ray Absorption Spectroscopy

Cho, B. I.; Engelhorn, K.; Correa, Alfredo A.; Ogitsu, Tadashi; Weber, Carsten; Lee, H. J.; Feng, Jun; Ni, P.; Ping, Yuan; Nelson, A. J.; Prendergast, David; Lee, R. W.; Falcone, R. W.; Heimann, Philip

doi:10.1103/physrevlett.106.167601

Cited by 132 publications

(120 citation statements)

References 24 publications

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“…2(d)), data are particularly scattered, however one can discern a twofold trend: a tangible attenuation of absorption at intermediate fluences followed by an increase above 1 J cm −2 . These findings are in good qualitative agreement with pioneering time resolved x-ray absorption spectroscopy (XAS) measurements carried out on laser-heated metals (Cu L 3 -edge, 18 Al K-edge, 19 and Ni L 3 -edge 20 ). In those experiments, a smearing of the absorption edge was noticed, as indicated by the red arrows in Fig.…”

supporting

confidence: 88%

Free electron laser-driven ultrafast rearrangement of the electronic structure in Ti

Principi

Giangrisostomi

Cucini

et al. 2015

Structural Dynamics

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High-energy density extreme ultraviolet radiation delivered by the FERMI seeded free-electron laser has been used to create an exotic nonequilibrium state of matter in a titanium sample characterized by a highly excited electron subsystem at temperatures in excess of 10 eV and a cold solid-density ion lattice. The obtained transient state has been investigated through ultrafast absorption spectroscopy across the Ti M2,3-edge revealing a drastic rearrangement of the sample electronic structure around the Fermi level occurring on a time scale of about 100 fs.

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supporting

confidence: 88%

Free electron laser-driven ultrafast rearrangement of the electronic structure in Ti

Principi

Giangrisostomi

Cucini

et al. 2015

Structural Dynamics

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“…Other studies of the K-edge shape changes in warm dense plasmas [19][20][21] have been made, but only for solid density or moderate compression of solid targets by a single shock. How the K edge moves in both strongly coupled and degenerate (extremely dense) plasmas is another important question that remains to be answered.…”

Section: Introductionmentioning

confidence: 99%

Continuum Lowering and Fermi-Surface Rising in Strongly Coupled and Degenerate Plasmas

Hu¹

2017

Phys. Rev. Lett.

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Continuum lowering is a well-known and important physics concept that describes the ionization potential depression (IPD) in plasmas caused by thermal-/pressure-induced ionization of outershell electrons. The existing IPD models are often used to characterize plasma conditions and to gauge opacity calculations. Recent precision measurements have revealed deficits in our understanding of continuum lowering in dense hot plasmas. However, these investigations have so far been limited to IPD in strongly coupled but nondegenerate plasmas. Here, we report a first-principles study of the K-edge shifting in both strongly coupled and fully degenerate carbon plasmas, with quantum molecular dynamics (QMD) calculations based on the all-electron density-functional theory (DFT). The resulted K-edge shifting versus plasma density, as a probe to the continuum lowering and the Fermi-surface rising, is found to be significantly different from predictions of existing IPD models. In contrast, a simple model of "single-atom-in-box" (SAIB), developed in this work, accurately predicts K-edge locations as what ab-initio calculations provide.2 PACS: 52.27. Gr, 52.25.Os, 52.70.La, For an isolated neutral atom or atomic ion, the ionization potentials (IP's) of electrons represent the energies required to free these electrons from their bound states. If photons are used to ionize the 1s-core electron of atoms or atomic ions, the photoabsorption spectrum exhibits a sharp edge (the so-called "K edge") above which the ionization probability is increased by orders of magnitude. For an isolated atom or ion, the K edge generally characterizes the ionization potential of 1s-core electron. Namely, the K-edge location is determined by E K-edge = IP = E C -E 1s , with the continuum level E C (E C = 0 for an isolated atom or ion) and the binding energy E 1s of the 1s-core electron. If atoms are immersed into a plasma, the thermal-/pressureinduced ionization of outer-shell electrons can cause the "continuum" to lower. Once the atomic continuum is lowered in a plasma, the ionization potential of bound electrons seems to depreciate. The analytical models 1-4 of ionization potential depreciation (IPD) are often used to infer plasma density/temperature conditions by measuring atomic K-edges in plasmas. They have also been extensively applied to alter the detailed opacity and equation-of-state (EOS) calculations of plasmas. 5-8 Consequently, this well-known physics concept of continuum lowering 1-4 is very important not only to plasma physics but also to planetary science, astrophysics, and high-energy-density physics.For its crucial importance to many fields, the IPD of atomic ions in plasmas has gained considerable attention over the past several years. These revisits have been motivated by recent experiments using both free-electron lasers to monitor K α emission spectra at Linac Coherent Light Source (LCLS) 9-11 and the hot dense plasma experiment at ORION. 12 These precision experiments have revealed the lack of a consistent picture about cont...

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“…This together with the introduction of Langevin thermostats [17] has proved successful in interpreting measured quantities [18,19]. This approach remains of active interest and, in recent years, * Corresponding author: vrizzi01@qub.ac.uk it has evolved into more elaborate methodologies where the nuclear motion is taken into account via classical molecular dynamics simulations, while electrons are treated at increasing levels of sophistication [20][21][22][23][24][25].…”

Section: Introductionmentioning

confidence: 99%

Electron-phonon thermalization in a scalable method for real-time quantum dynamics

et al. 2016

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We present a quantum simulation method that follows the dynamics of out-of-equilibrium many-body systems of electrons and oscillators in real time. Its cost is linear in the number of oscillators and it can probe time scales from attoseconds to hundreds of picoseconds. Contrary to Ehrenfest dynamics, it can thermalize starting from a variety of initial conditions, including electronic population inversion. While an electronic temperature can be defined in terms of a nonequilibrium entropy, a Fermi-Dirac distribution in general emerges only after thermalization. These results can be used to construct a kinetic model of electron-phonon equilibration based on the explicit quantum dynamics.

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Electronic Structure of Warm Dense Copper Studied by Ultrafast X-Ray Absorption Spectroscopy

Cited by 132 publications

References 24 publications

Free electron laser-driven ultrafast rearrangement of the electronic structure in Ti

Free electron laser-driven ultrafast rearrangement of the electronic structure in Ti

Continuum Lowering and Fermi-Surface Rising in Strongly Coupled and Degenerate Plasmas

Electron-phonon thermalization in a scalable method for real-time quantum dynamics

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