Observation of a highly conductive warm dense state of water with ultrafast pump–probe free-electron-laser measurements
Observation of a highly conductive warm dense state of water with ultrafast pump–probe free-electron-laser measurements
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通过超快泵浦探针自由电子激光测量观察水的高导电性暖密态
DOI：
10.1063/5.0043726
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发表时间：
2021
影响因子：
5.1
通讯作者：
S. Glenzer
中科院分区：
文献类型：
--
作者：
Zhijiang Chen;X. Na;C. Curry;S. Liang;M. French;A. Descamps;D. DePonte;J. Koralek;J. B. Kim;S. Lebovitz;M. Nakatsutsumi;B. Ofori;R. Redmer;C. Roedel;M. Schörner;S. Skruszewicz;P. Sperling;S. Toleikis;M. Mo;S. Glenzer
水在极端温度和密度下的电导率在模拟行星磁场中起着核心作用。实验数据对于测试高能量密度水的理论和评估外星生命的可能发展和存在至关重要。这些状态在生物学和化学研究中也很重要，当水中的样品被限制并使用超快光学或自由电子激光（FEL）激发时。在这里，我们利用飞秒光学激光测量瞬态反射和透射的水片样品均匀加热的13.6 nm的自由电子激光接近高导电状态的电子温度超过20 000 K。该实验探测了水通过高能量密度相空间的轨迹，并提供了对光频下折射率、载流子密度和AC电导率变化的见解。在激发能量密度超过10 MJ/kg时，折射率福尔斯下降到n = 0.7，热激发的自由载流子密度达到ne = 5 × 1027 m-3，这比直接光电离产生的电子载流子高出一个数量级。由于临界电子密度屏蔽电磁波，观察到显着的镜面反射。测得的光学电导率达到2 × 104 S/m，这个值比液态的简单金属低一到两个数量级。在电子温度低于15 000 K时，实验结果与密度泛函理论/分子动力学模拟的理论计算结果吻合得很好。随着温度的升高，电子密度增加，系统接近费米分布。在这种情况下，电导率同意更好的预测从Ziman理论的液体金属。
The electrical conductivity of water under extreme temperatures and densities plays a central role in modeling planetary magnetic fields. Experimental data are vital to test theories of high-energy-density water and assess the possible development and presence of extraterrestrial life. These states are also important in biology and chemistry studies when specimens in water are confined and excited using ultrafast optical or free-electron lasers (FELs). Here we utilize femtosecond optical lasers to measure the transient reflection and transmission of ultrathin water sheet samples uniformly heated by a 13.6 nm FEL approaching a highly conducting state at electron temperatures exceeding 20 000 K. The experiment probes the trajectory of water through the high-energy-density phase space and provides insights into changes in the index of refraction, charge carrier densities, and AC electrical conductivity at optical frequencies. At excitation energy densities exceeding 10 MJ/kg, the index of refraction falls to n = 0.7, and the thermally excited free-carrier density reaches ne = 5 × 1027 m−3, which is over an order of magnitude higher than that of the electron carriers produced by direct photoionization. Significant specular reflection is observed owing to critical electron density shielding of electromagnetic waves. The measured optical conductivity reaches 2 × 104 S/m, a value that is one to two orders of magnitude lower than those of simple metals in a liquid state. At electron temperatures below 15 000 K, the experimental results agree well with the theoretical calculations using density-functional theory/molecular-dynamics simulations. With increasing temperature, the electron density increases and the system approaches a Fermi distribution. In this regime, the conductivities agree better with predictions from the Ziman theory of liquid metals.
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DOI：
10.1103/physreve.99.047201
发表时间：
2019
期刊：
Physical review. E
影响因子：
--
作者：
B. B. L. Witte;G. Röpke;P. Neumayer;M. French;P. Sperling;V. Recoules;S. H. Glenzer;R. Redmer
通讯作者：
R. Redmer
影响因子：
8.6
作者：
Sperling, P.;Gamboa, E. J.;Glenzer, S. H.
通讯作者：
Glenzer, S. H.
影响因子：
8.6
作者：
U. Zastrau;P. Sperling;M. Harmand;A. Becker;T. Bornath;R. Bredow;S. Dziarzhytski;T. Fennel;L. Fletcher;Eckhart Förster;S. Göde;G. Gregori;V. Hilbert;D. Hochhaus;B. Holst;T. Laarmann;H. Lee;T. Ma;J. Mithen;R. Mitzner;C. Murphy;M. Nakatsutsumi;P. Neumayer;A. Przystawik;S. Roling;M. Schulz;B. Siemer;S. Skruszewicz;J. Tiggesbäumker;S. Toleikis;T. Tschentscher;T. White;M. Wöstmann;H. Zacharias;T. Döppner;S. Glenzer;R. Redmer
通讯作者：
U. Zastrau;P. Sperling;M. Harmand;A. Becker;T. Bornath;R. Bredow;S. Dziarzhytski;T. Fennel;L. Fletcher;Eckhart Förster;S. Göde;G. Gregori;V. Hilbert;D. Hochhaus;B. Holst;T. Laarmann;H. Lee;T. Ma;J. Mithen;R. Mitzner;C. Murphy;M. Nakatsutsumi;P. Neumayer;A. Przystawik;S. Roling;M. Schulz;B. Siemer;S. Skruszewicz;J. Tiggesbäumker;S. Toleikis;T. Tschentscher;T. White;M. Wöstmann;H. Zacharias;T. Döppner;S. Glenzer;R. Redmer
影响因子：
3.2
作者：
Redmer, Ronald;Mattsson, Thomas R.;French, Martin
通讯作者：
French, Martin
影响因子：
62.1
作者：
Zhou HX;Pang X
通讯作者：
Pang X