Article
Physics, Multidisciplinary
Antoine Camper, Amelie Ferre, Valerie Blanchet, Dominique Descamps, Nan Lin, Stephane Petit, Robert Lucchese, Pascal Salieres, Thierry Ruchon, Yann Mairesse
Summary: By resolving the emission from two families of electronic quantum paths, this study avoids the need for advanced theoretical modeling and provides insights into attosecond electronic and vibrational dynamics. The quantum-path resolved spectroscopy opens up prospects for investigating ultrafast ionic dynamics, including charge migration.
PHYSICAL REVIEW LETTERS
(2023)
Article
Chemistry, Physical
Yuki Kobayashi, Stephen R. Leone
Summary: This article highlights recent advances in time-resolved x-ray absorption spectroscopy (tr-XAS) for studying coherent phenomena. tr-XAS, using isolated attosecond pulses as the light source, provides unparalleled time and state sensitivities, making it suitable for studying valence electronic dynamics in various materials. The latest studies have demonstrated the capabilities of tr-XAS in characterizing electronic-structural coherence in small molecules and light-matter interactions in solids.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Chemistry, Physical
Deependra Jadoun, Markus Kowalewski
Summary: Conical Intersections (CIs) are common in molecular and biological systems, opening up ultrafast nonradiative decay channels. While photoelectron spectroscopy with femtosecond pulses can resolve the involved electronic states in the energy domain, observing the created electronic coherence in the time domain requires probe pulses with larger bandwidth.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2021)
Article
Optics
Mina R. Bionta, Felix Ritzkowsky, Marco Turchetti, Yujia Yang, Dario Cattozzo Mor, William P. Putnam, Franz X. Kaertner, Karl K. Berggren, Phillip D. Keathley
Summary: This on-chip optoelectronic device is capable of sampling low-energy near-infrared waveforms with sub-optical-cycle resolution under ambient conditions. By using resonant nanoantennas for field-driven photoemission, the device can create attosecond electron bursts to probe weak optical waveforms and reveal the localized plasmonic dynamics of the emitting nanoantennas. Applications include broadband time-domain spectroscopy, time-domain analysis of nonlinear phenomena, and detailed investigations of strong-field light-matter interactions.
Article
Multidisciplinary Sciences
Rolf Gersbacher, John T. Broad
Summary: The J-Matrix approach is extended to the time-dependent Schrodinger equation for one electron atoms in external few cycle attosecond fields. The wave function is expanded in square integrable Sturmian functions and an equation system for the transition amplitudes is established. Boundary conditions are imposed at the L-2 boundary grid to minimize reflections and achieve outgoing wave behavior in the asymptotic region.
SCIENTIFIC REPORTS
(2022)
Article
Multidisciplinary Sciences
Bradley D. Frank, Saveh Djalali, Agata W. Baryzewska, Paolo Giusto, Peter H. Seeberger, Lukas Zeininger
Summary: Researchers have achieved chemotactic motion of emulsion droplets, which can be controllably altered by modifying the droplets' geometry and composition. This finding has implications for the design of smart and adaptive microbots.
NATURE COMMUNICATIONS
(2022)
Article
Optics
Ningliang Liu, Chunyang Zhai, Qianguang Li, Yingbin Li, Benhai Yu
Summary: Photoelectron holography in strong field tunneling ionization has been used to probe the attosecond electron dynamics in more complex molecules, such as the triatomic molecule H-3. By solving the time-dependent Schrodinger equation, researchers have demonstrated the ultrafast charge migration in H-3 could be retrieved from the holographic fringes in the photoelectron momentum distribution. This study suggests that the concept of photoelectron holography can be extended to explore attosecond electron dynamics in complex molecules, which is crucial for the emerging field of attosecond chemistry.
OPTICS COMMUNICATIONS
(2021)
Article
Multidisciplinary Sciences
Alexander Neef, Samuel Beaulieu, Sebastian Hammer, Shuo Dong, Julian Maklar, Tommaso Pincelli, R. Patrick Xian, Martin Wolf, Laurenz Rettig, Jens Pflaum, Ralph Ernstorfer
Summary: Singlet fission can double the number of excited charge carriers by transforming a singlet exciton into two triplet excitons, thereby boosting photovoltaic efficiency. The primary step of singlet fission, the creation of correlated triplet pairs, has multiple proposed mechanisms but lacks consensus. This study used time- and angle-resolved photoemission spectroscopy to observe the primary step of singlet fission in crystalline pentacene and found evidence of a charge-transfer mediated mechanism with hybridization of Frenkel and charge-transfer states in the lowest bright singlet exciton. The orbital and localization characteristics of the exciton wave functions were analyzed, providing insights into the mechanics of molecular systems and topological materials.
Article
Optics
Li Guo, Yi Jia, Mingqing Liu, Xinyan Jia, Shilin Hu, Ronghua Lu, ShenSheng Han, Jing Chen
Summary: Using a Wigner distribution-like function based on the strong field approximation theory, we obtained the time-energy distributions and ionization time distributions of electrons ionized by XUV pulses alone or in the presence of IR pulses. The interference of low-energy structures plays a key role in shaping the ionization time distribution, with the electron emission direction, carrier-envelope phase, and counter-rotating term all affecting the distribution. Furthermore, the presence of the IR field not only alters the electron's final kinetic energy but also changes its emission time, with less impact seen on electrons from atoms with higher ionization energy.
Article
Optics
Mao-Yun Ma, Jun-Ping Wang, Wen-Quan Jing, Zhong Guan, Zhi-Hong Jiao, Guo-Li Wang, Jian-Hong Chen, Song-Feng Zhao
Summary: This study investigates atomic orbital resolved vortex-shaped photoelectron momentum distributions and ionization probabilities of neon in counter-rotating circularly polarized attosecond pulses. The number of spiral arms in vortex patterns corresponds to absorbed photons and the rotational symmetry changes with the initial state. Ionization probabilities are weakly dependent on the magnetic quantum number for two- and three-photon ionization. Single-photon ionization is preferred when the electron and laser field corotate, with different probabilities for 2p(-) and 2p(+) states depending on time delay and wavelength.
Article
Chemistry, Physical
Tara J. Michael, Hannah M. Ogden, Amy S. Mullin
Summary: In this study, state-resolved distributions and collision dynamics of optically centrifuged CO molecules with orientated angular momentum are investigated using high-resolution transient IR absorption spectroscopy. The results show a reversal in rotational distributions with a maximum population at J = 62, as well as the influence of collisions on the rotational energy transfer and relaxation pathways. Additionally, the study reveals polarization-sensitive characteristics and translational temperatures of CO molecules excited to high rotational levels.
JOURNAL OF CHEMICAL PHYSICS
(2021)
Article
Nanoscience & Nanotechnology
Nicholas A. Nobile, John R. Erickson, Carlos Rios, Yifei Zhang, Juejun Hu, Steven A. Vitale, Feng Xiong, Nathan Youngblood
Summary: Optical phase-change materials have great potential for various applications, but their high melting temperatures and fast quenching rates pose challenges for large-scale integration. In this study, the thermo-optic effect in Ge2Sb2Te5 was investigated using temperature-dependent ellipsometry, and an experimental technique was developed to measure the thermal properties of electrically programmable phase-change devices.
Article
Optics
Wenqing Li, Xiaosong Zhu, Pengfei Lan, Peixiang Lu
Summary: This paper revisits high-order harmonic generation (HHG) in high optical chirality corotating bicircular fields and extends the study to a frequency ratio higher than 1:2. By analyzing the classical trajectories, it is shown that the hindering effect of the Coriolis force on HHG decreases with the frequency ratio. Based on these findings, a method for producing highly elliptically polarized attosecond pulses using the corotating bicircular field with a frequency ratio of 1:3 is proposed. A comparison with extensively studied counter-rotating configurations is also made, and the results demonstrate the validity and superiority of the corotating configurations in terms of higher ellipticity and yield of generated attosecond pulses.
Article
Physics, Multidisciplinary
Yu-Ning Yang, Su-Qi Chen, Zhao-Han Zhang, Hui Jiang, Min Chen, Yang Li, Feng He
Summary: This paper builds a model to explain the high harmonic generation in combined EUV and midinfrared laser fields. By embodying the spin-resolved three-electron dynamics, the model results agree with the time-dependent Schrodinger equation simulations including three active electrons. The intriguing picture explored in this work is fundamentally distinguished from scenarios relying on spin-orbit coupling.
PHYSICAL REVIEW LETTERS
(2023)
Review
Multidisciplinary Sciences
Francisco J. Garcia-Vidal, Cristiano Ciuti, Thomas W. Ebbesen
Summary: In the past decade, there has been a surge of interest in using hybrid light-matter states to control the properties of matter and chemical reactivity. Experimental and theoretical studies have shown that these hybrid states can enhance properties like transport, magnetism, and superconductivity, as well as modify (bio)chemical reactivity. This multidisciplinary field has great potential for further exploration.
Article
Biochemistry & Molecular Biology
Michal Stransky, Zoltan Jurek, Robin Santra, Adrian P. Mancuso, Beata Ziaja
Summary: In this work, tree-algorithm based solvers were incorporated into the molecular dynamics code XMDYN for the first time, improving its performance and enabling computationally efficient simulations of X-ray irradiated large atomic assemblies.
Article
Optics
Otfried Geffert, Daria Kolbasova, Andrea Trabattoni, Francesca Calegari, Robin Santra
Summary: The field of ultrafast spectroscopy relies on precise characterization of ultrashort laser pulses. This study proposes an in situ characterization scheme based on first-principles calculations and introduces a machine-learning algorithm to reconstruct the pulse length and spectral width from the autocorrelation pattern.
Article
Chemistry, Physical
Cecilia M. Casadei, Ahmad Hosseinizadeh, Gebhard F. X. Schertler, Abbas Ourmazd, Robin Santra
Summary: Time-resolved serial femtosecond crystallography (TR-SFX) allows for the study of protein dynamics with atomic resolution on sub-picosecond timescales. In this work, the authors propose a novel approach called low-pass spectral analysis (LPSA) to improve the analysis of TR-SFX data. LPSA projects the data onto a subspace defined by trigonometric functions, attenuating high-frequency features and facilitating the retrieval of underlying dynamics. The authors demonstrate the effectiveness of LPSA in reconstructing dynamics and compare it to other existing data analysis techniques.
STRUCTURAL DYNAMICS-US
(2022)
Article
Chemistry, Physical
Sourav Banerjee, Zoltan Jurek, Malik Muhammad Abdullah, Robin Santra
Summary: This study aims to extend the XMDYN toolkit to treat chemical bonds and investigate the impact of charge rearrangement on the time evolution by simulating the interaction of a highly intense x-ray pulse with an amino acid. The discussion also addresses the capability of the classical MD based approach, XMDYN, to capture the charge-rearrangement-enhanced x-ray ionization of molecules effect.
STRUCTURAL DYNAMICS-US
(2022)
Article
Chemistry, Physical
Cecilia M. Casadei, Ahmad Hosseinizadeh, Spencer Bliven, Tobias Weinert, Jorg Standfuss, Russell Fung, Gebhard F. X. Schertler, Robin Santra
Summary: Low-pass spectral analysis (LPSA) is an effective algorithm for retrieving dynamics in model data affected by incompleteness and weighting errors. In this study, LPSA is applied to experimental time-resolved crystallography data and the parametric sensitivity is analyzed. The presence of high-frequency contamination in dynamical modes is investigated using synthetic data with various uncertainties and errors. A method is proposed to handle missing observations and improved dynamics retrieval is achieved.
STRUCTURAL DYNAMICS-US
(2023)
Article
Multidisciplinary Sciences
Zhong Yin, Yi-Ping Chang, Tadas Balciunas, Yashoj Shakya, Aleksa Djorovic, Geoffrey Gaulier, Giuseppe Fazio, Robin Santra, Ludger Inhester, Jean-Pierre Wolf, Hans Jakob Worner
Summary: Researchers have revealed the femtosecond proton-transfer dynamics in ionized urea dimers in aqueous solution using table-top water-window X-ray absorption spectroscopy. By combining quantum-mechanical and molecular-mechanics calculations, they were able to identify the subsequent rearrangement of the urea dimer and the associated change of the electronic structure with site selectivity. These findings highlight the potential of table-top X-ray absorption spectroscopy in elucidating ultrafast dynamics in biomolecular systems.
Article
Multidisciplinary Sciences
E. Juncheng, Michal Stransky, Zhou Shen, Zoltan Jurek, Carsten Fortmann-Grote, Richard Bean, Robin Santra, Beata Ziaja, Adrian P. Mancuso
Summary: This study investigates the impact of water layer thickness and radiation damage on orientation recovery from diffraction patterns of the nitrogenase iron protein. The results show that while a water layer mitigates protein damage, the noise generated by the scattering from it can introduce challenges for orientation recovery and is anticipated to cause problems in the phase retrieval process.
SCIENTIFIC REPORTS
(2023)
Article
Optics
Yashoj Shakya, Ralph Welsch, Ludger Inhester, Robin Santra
Summary: Simulations of coupled electronic and nuclear dynamics in molecules are computationally challenging and limited to model systems or small molecules. The approach presented in this study combines Tully's fewest switches surface hopping (FSSH) with ring-polymer molecular dynamics (RPMD) to overcome the limitations of FSSH in describing electronic coherences and decoherence phenomena. By incorporating decoherence effects through an electronic density-matrix formulation, this method captures a crucial decoherence mechanism missing in FSSH and provides a superior description of electronic coherences compared to earlier attempts at combining RPMD and FSSH.
Article
Physics, Multidisciplinary
Arunangshu Debnath, Robin Santra
Summary: We present a theoretical formulation for interpreting high-energy x-ray diffraction measurements using synchrotron radiation sources. The formulation allows classification of physical resources contributing to the correlation signatures and provides a unique perspective for structural imaging studies. It also offers a framework necessary for theoretical developments of associated reconstruction algorithms.
PHYSICAL REVIEW RESEARCH
(2023)
Article
Optics
Laura Budewig, Sang-Kil Son, Robin Santra
Summary: We propose a theoretical framework to study the state-resolved ionization dynamics of neon atoms driven by ultraintense x-ray free-electron-laser pulses. By combining a state-resolved electronic-structure calculation with a Monte Carlo rate-equation method, we are able to investigate the dynamics based on time-dependent state populations. Our results show that both configuration-based and state-resolved calculations yield similar charge-state distributions, except when resonant excitations are involved. Furthermore, we analyze time-resolved spectra of ions, electrons, and photons to explore frustrated absorption during the ionization dynamics of neon atoms.
Article
Physics, Multidisciplinary
Niels Breckwoldt, Sang-Kil Son, Tommaso Mazza, Aljoscha Roerig, Rebecca Boll, Michael Meyer, Aaron C. LaForge, Debadarshini Mishra, Nora Berrah, Robin Santra
Summary: X-ray free-electron lasers (XFELs) bring new possibilities for probing and manipulating atomic and molecular dynamics with unprecedented resolution. However, accurately comparing experimental results with theoretical simulations requires precise characterization of the spatial and temporal profile of the X-ray pulses. In this study, we propose a calibration scheme based on Bayesian optimization to accurately determine the pulse duration and spatial fluence distribution profile of intense XFEL pulses. This method can serve as a comprehensive tool for characterizing ultraintense and ultrafast X-ray pulses.
PHYSICAL REVIEW RESEARCH
(2023)
Article
Optics
Daria Kolbasova, Robin Santra
Summary: Building on a previous strategy, this study presents an efficient alternative approach for characterizing ultrashort low-frequency laser pulses in situ. By using quantum-mechanical calculations, the researchers simulate the ionization of rare-gas atoms in strong fields and generate autocorrelation patterns for femtosecond laser pulses. They investigate the nonperturbative and nonlinear dependence of these patterns on pulse characteristics and propose an analytical function to describe them. The function's parameters and supervised machine learning are then utilized to retrieve key pulse parameters from the autocorrelation patterns produced via strong-field ionization. This approach offers advantages for experimental data applications.
Article
Optics
Stanislaw Wirok-Stoletow, Rui Jin, Daria Kolbasova, Sang-Kil Son, Andrew Aquila, Robin Santra
Summary: We theoretically investigate the formation of highly charged ions in a germanium solid driven by intense X-ray pulses and its effect on the cross sections for nonsequential two-photon absorption. Our study finds that the formation of charged ions in germanium is quick under the given experimental conditions, but the cross sections for nonsequential two-photon absorption are insensitive to different charge states.
Article
Physics, Fluids & Plasmas
Rui Jin, Zoltan Jurek, Robin Santra, Sang-Kil Son
Summary: This study incorporates a recently proposed treatment of transient ionization potential depression (IPD) into plasma dynamics simulations, and demonstrates the importance of the IPD effects in theoretical modeling of dense plasmas by comparing two simulations.
Article
Chemistry, Physical
Muhammad Shafiq Bin Mohd Yusof, Hongwei Song, Tushar Debnath, Bethany Lowe, Minghui Yang, Zhi-Heng Loh
Summary: Proton transfer reactions play a crucial role in chemical and biological processes. This study investigates the ultrafast proton transfer dynamics of the aqueous phenol radical cation using femtosecond spectroscopy and quantum dynamics calculations. The results suggest that proton transfer occurs on a very fast timescale of about 0.1 ps. These findings contribute to a better understanding of the ultrafast proton transfer triggered by photoionization.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2022)