Coupled-cluster techniques for computational chemistry: The CFOUR program package

The Journal of Chemical Physics, Journal Year: 2020, Volume and Issue: 152(21)

Published: June 3, 2020

An up-to-date overview of the CFOUR program system is given. After providing a brief outline evolution since its inception in 1989, comprehensive presentation given well-known capabilities for high-level coupled-cluster theory and application to molecular properties. Subsequent this generally background information, much remaining content focuses on lesser-known CFOUR, most which have become available public only recently or will near future. Each these new features illustrated by representative example, with additional discussion targeted educating users as classes applications that are now enabled capabilities. Finally, some speculation about future directions given, mode distribution support outlined.

Language: Английский

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Oxygen K-edge X-ray Absorption Spectra

Chemical Reviews, Journal Year: 2020, Volume and Issue: 120(9), P. 4056 - 4110

Published: April 10, 2020

We review oxygen K-edge X-ray absorption spectra of both molecules and solids. start with an overview the main experimental aspects measurements including sources, monochromators, detection schemes. Many recent studies combine time spatially resolved and/or operando conditions. The theoretical conceptual approximations for simulation K-edges are discussed in Theory section. subsequently discuss atoms ions, binary molecules, water, larger containing oxygen, biomolecular systems. largest part deals results solid oxides, starting from s- p-electron oxides. Examples simulations these oxides introduced order to show how accurate a DFT description can be case s p electron overlap. general analysis 3d transition metal discussions crystal field effect effects trends oxidation state covalency. In addition concepts, we give systematic element by element, s-, p-, d-, f-electron

Language: Английский

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Ultrafast Spectroscopy: State of the Art and Open Challenges

Journal of the American Chemical Society, Journal Year: 2019, Volume and Issue: 142(1), P. 3 - 15

Published: Dec. 4, 2019

Ultrafast spectroscopy techniques use sequences of ultrashort light pulses (with femto- to attosecond durations) study photoinduced dynamical processes in atoms, molecules, nanostructures, and solids. This field research has experienced an impetuous growth recent years, due the technological progress generation development sophisticated spectroscopic techniques, which greatly increase amount information on process under study. paper aims at providing a non-exhaustive overview state art pointing out future challenges. We first review ultrafast optics, enabled broadly tunable with duration down few optical cycles; we then discuss pump–probe technique, showing examples its capability combine very high time resolution, regime, broad spectral coverage; introduce two-dimensional present results that demonstrate additional content provided by combination temporal resolution. Next, achievements X-ray electron diffraction, provide time-dependent structural photochemical processes, conclude critical analysis open challenges field.

Language: Английский

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Transient absorption spectroscopy using high harmonic generation: a review of ultrafast X-ray dynamics in molecules and solids

Philosophical Transactions of the Royal Society A Mathematical Physical and Engineering Sciences, Journal Year: 2019, Volume and Issue: 377(2145), P. 20170463 - 20170463

Published: April 1, 2019

Attosecond science opened the door to observing nuclear and electronic dynamics in real time has begun expand beyond its traditional grounds. Among several spectroscopic techniques, X-ray transient absorption spectroscopy become key understanding matter on ultrafast scales. In this review, we illustrate capabilities of unique tool through a number iconic experiments. We outline how coherent broadband radiation, emitted high-harmonic generation, can be used follow increasingly complex systems. Experiments performed both molecules solids are discussed at length, scales ranging from attoseconds picoseconds, perturbative or strong-field excitation regimes. This article is part theme issue 'Measurement structural with X-rays'.

Language: Английский

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New and Efficient Equation-of-Motion Coupled-Cluster Framework for Core-Excited and Core-Ionized States

Journal of Chemical Theory and Computation, Journal Year: 2019, Volume and Issue: 15(5), P. 3117 - 3133

Published: April 9, 2019

We present a fully analytical implementation of the core-valence separation (CVS) scheme for equation-of-motion (EOM) coupled-cluster singles and doubles (CCSD) method calculations core-level states. Inspired by CVS idea as originally formulated Cederbaum, Domcke, Schirmer, pure valence excitations are excluded from EOM target space frozen-core approximation is imposed on reference-state amplitudes multipliers. This yields an efficient, robust, practical, numerically balanced EOM-CCSD framework excitation ionization energies well state transition properties (e.g., spectral intensities, natural transition, Dyson orbitals) both ground excited The errors in absolute excitation/ionization relative to experimental reference data order 0.2-3.0 eV, depending K-edge considered basis set used, shifts systematic each edge. Compared previously proposed where was applied posteriori projection only during solution eigenvalue equations, new computationally cheaper. It also achieves better cancellation errors, yielding similar profiles but with core that systematically closer corresponding data. Among presented results transient-state X-ray absorption spectra, relevant interpretation UV-pump/X-ray probe experiments.

Language: Английский

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Molecular Structure and Modeling of Water–Air and Ice–Air Interfaces Monitored by Sum-Frequency Generation

Chemical Reviews, Journal Year: 2020, Volume and Issue: 120(8), P. 3633 - 3667

Published: March 6, 2020

From a glass of water to glaciers in Antarctica, water–air and ice–air interfaces are abundant on Earth. Molecular-level structure dynamics at these key for understanding many chemical/physical/atmospheric processes including the slipperiness ice surfaces, surface tension water, evaporation/sublimation water. Sum-frequency generation (SFG) spectroscopy is powerful tool probe molecular-level because SFG can specifically topmost interfacial molecules separately from bulk sensitive molecular conformation. Nevertheless, experimental has several limitations. For example, cannot provide information depth interface how orientation varies with distance surface. By combining simulation techniques, one directly compare data simulated spectra, allowing us unveil interfaces. Here, we present an overview different protocols available spectra calculations. We systematically computed approaches, revealing advantages disadvantages methods. Furthermore, account findings through combined experiments simulations future challenges aqueous

Language: Английский

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Progress on table-top isolated attosecond light sources

Nature Photonics, Journal Year: 2022, Volume and Issue: 16(4), P. 267 - 278

Published: March 7, 2022

Language: Английский

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Attosecond spectroscopy for the investigation of ultrafast dynamics in atomic, molecular and solid-state physics

Reports on Progress in Physics, Journal Year: 2022, Volume and Issue: 85(6), P. 066401 - 066401

Published: March 16, 2022

Since the first demonstration of generation attosecond pulses (1 as = 10-18s) in extreme-ultraviolet spectral region, several measurement techniques have been introduced, at beginning for temporal characterization pulses, and immediately after investigation electronic nuclear ultrafast dynamics atoms, molecules solids with unprecedented resolution. The spectroscopic tools established last two decades, together development sophisticated theoretical methods interpretation experimental outcomes, allowed to unravel investigate physical processes never observed before, such delay photoemission from atoms solids, motion electrons prompt ionization which precede any notable motion, evolution tunneling process dielectrics, many others. This review focused on applications solids. Thanks introduction ongoing developments new techniques, science is rapidly moving towards investigation, understanding control coupled electron-nuclear increasingly complex systems, ever more accurate complete techniques. Here we will most common presenting latest results

Language: Английский

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Entangled photons enabled time-frequency-resolved coherent Raman spectroscopy and applications to electronic coherences at femtosecond scale

Light Science & Applications, Journal Year: 2022, Volume and Issue: 11(1)

Published: Sept. 14, 2022

Quantum entanglement has emerged as a great resource for spectroscopy and its importance in two-photon spectrum microscopy been demonstrated. Current studies focus on the absorption, whereas Raman with quantum still remains elusive, outstanding issues of temporal spectral resolutions. Here we study new capabilities provided by entangled photons coherent spectroscopy. An ultrafast frequency-resolved is developed condensed-phase molecules, to probe electronic vibrational coherences. Using correlation between photons, signal shows capability both resolutions not accessible either classical pulses or fields without entanglement. We develop microscopic theory this spectroscopy, revealing coherence dynamics even at timescale 50fs. This suggests paradigms optical signals potential push detection below standard limit.

Language: Английский

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Next generation lanthanide doped nanoscintillators and photon converters

eLight, Journal Year: 2022, Volume and Issue: 2(1)

Published: Sept. 19, 2022

Abstract Scintillators are of significance for the realization indirect X-ray detection and excited optical luminescence (XEOL) imaging. However, commercial bulk scintillators not only require complex fabrication procedures, but also exhibit non-tunable XEOL wavelength poor device processability. Moreover, thick crystals usually generate light scattering followed by evident signal crosstalk in a photodiode array. Lanthanide doped fluoride nanoscintillators (NSs) prepared with low-temperature wet-chemical method possess several advantages, such as low toxicity, cheap cost, convenient processability adjustable emission wavelengths from ultraviolet to visible extending second near infrared window. In addition, they long persistent (XEPL) making them suitable broadening scope their applications. This review discusses summarizes XEPL characteristics lanthanide NSs. We discuss design strategies nanostructures that allow manipulation excitation dynamics core–shell geometry simultaneously produce XEOL, XEPL, well photon upconversion downshifting, enabling at multiple varying time scale profile. The ends discussion existing challenges advancing this field, presents our subjective insight into areas further multidisciplinary opportunities.

Language: Английский

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