Simulation of Ultra-Fast Dynamics Effects in Resonant Inelastic X-ray Scattering of Gas-Phase Water

Fouda, Adam E. A.; Purnell, Gregory I.; Besley, Nicholas A.

doi:10.1021/acs.jctc.8b00211

Cited by 18 publications

(28 citation statements)

References 90 publications

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“…Another factor that can be important is nuclear dynamics which can have a significant effect on the maps, and this is further complicated by the dynamics of the core-excited intermediate state may differ significantly from the ground state.RIXS data can be presented as a RIXS map where the intensity is plotted as a function of the excitation and emission energies. High quality experimental data is for the RIXS map of the water molecule is available,57 and we have explored the simulation of the RIXS map based upon different quantum chemical methods including ADC and TDDFT 58. The calculated RIXS maps based upon the TDDFT calculations are shown in Figure10.…”

mentioning

confidence: 99%

Density Functional Theory Based Methods for the Calculation of X-ray Spectroscopy

Besley

2020

Acc. Chem. Res.

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108

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Conspectus The availability of new light sources combined with the realization of the unique capabilities of spectroscopy in the X-ray region has driven tremendous advances in the field of X-ray spectroscopy. Currently, these techniques are emerging as powerful analytical tools for the study of a wide range of problems encompassing liquids, materials, and biological systems. Time-resolved measurements add a further dimension to X-ray spectroscopy, opening up the potential to resolve ultrafast chemical processes at an atomic level. X-ray spectroscopy encompasses a range of techniques which provide complementary information, and these include X-ray photoelectron spectroscopy (XPS), X-ray absorption spectroscopy (XAS), X-ray emission spectroscopy (XES), and resonant inelastic X-ray scattering (RIXS). In many studies, the interpretation of the experimental data relies upon calculations to enable the nature of the underlying molecular structure, electronic structure, and bonding to be revealed. Density functional theory (DFT) based methods are some of the most widely used methods for the simulation of X-ray spectra. In this Account, we focus on our recent contributions to the simulation of a range of X-ray spectroscopic techniques using DFT and linear-response time-dependent density functional theory (TDDFT) and show how these methods can provide a computational toolkit for the simulation of X-ray spectroscopy. The importance of the exchange-correlation functional for the calculation of XAS is discussed, and the introduction of short-range corrected functionals is described. The application of these calculations to study large systems through the use of efficient implementations of TDDFT will be highlighted, with the use of these methods illustrated through studies of ionic liquids and transition metal complexes. The extension of TDDFT to calculate XES through the use of a reference determinant for the core-ionized state will be described, and the factors that affect the accuracy of the computed spectra discussed. The application of these approaches will be illustrated through the study of a range of organic molecules and transition metal complexes, which also show how going beyond the dipole approximation in determining the transition intensities can be critical. The application of these approaches to the simulation of the RIXS spectrum of water will also be described, highlighting how ultrafast dynamics on the femtoscale time scale are evident in the measured spectra. In these calculations, the description of the core-ionized and core-excited states becomes increasingly important, and the role of the basis set in accurately describing these states will be explored.

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confidence: 99%

Density Functional Theory Based Methods for the Calculation of X-ray Spectroscopy

Besley

2020

Acc. Chem. Res.

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108

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“…In this approach, X‐ray emission spectra are computed for different core‐excited states 22,166,167,208‐213 . This can be achieved using TDDFT by using a reference determinant corresponding to the relevant core‐excited state 214 . To go beyond a RXES picture it is necessary to determine the RIXS cross‐sections.…”

Section: Other X‐ray Spectroscopic Techniquesmentioning

confidence: 99%

“…This can be done using the Kramers–Heisenberg (KH) formalism, 215‐219 and a semiclassical approximation to the KH equation has been introduced and applied to study hydrogen bonding liquids 220‐223 . There have been relatively few attempts to simulate a complete RIXS map, but studies of the gas‐phase water molecule have been reported 16,212,214 . A study on the water molecule compared RIXS maps simulated based upon ADC(2)‐x and TDDFT calculations of the absorption and emission processes 214 .…”

Section: Other X‐ray Spectroscopic Techniquesmentioning

confidence: 99%

“…A further challenge is evident in the RIXS of the water molecule, where some of the observed features are associated with molecular dissociation that occurs in the core‐excited intermediate states 205 . These effects can be incorporated into the simulations through conformational sampling of both the ground (initial) and core‐excited (intermediate) states 214 . More recently, TDDFT with a restricted subspace approximation has been used to simulate the RIXS of larger molecules including 2‐thiopyridone 127 .…”

Section: Other X‐ray Spectroscopic Techniquesmentioning

confidence: 99%

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Modeling of the spectroscopy of core electrons with density functional theory

Besley

2021

WIREs Comput Mol Sci

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104

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The availability of X‐ray light sources with increased resolution and intensity has provided a foundation for increasingly sophisticated experimental studies exploiting the spectroscopy of core electrons to probe fundamental chemical, physical, and biological processes. Quantum chemical calculations can play a critical role in the analysis of these experimental measurements. The relatively low computational cost of density functional theory (DFT) and time‐dependent density functional theory (TDDFT) make them attractive choices for simulating the spectroscopy of core electrons. An overview of current developments to apply DFT and TDDFT to study the key techniques of X‐ray photoelectron spectroscopy, X‐ray absorption spectroscopy, X‐ray emission spectroscopy, and resonant inelastic X‐ray scattering is presented. Insight into the accuracy that can be achieved, in conjunction with an examination of the limitations and challenges to modeling the spectroscopy of core electrons with DFT is provided. This article is categorized under: Electronic Structure Theory > Ab Initio Electronic Structure Methods Theoretical and Physical Chemistry > Spectroscopy Electronic Structure Theory > Density Functional Theory

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“…The black line shows the spectrum calculated at the ground state optimised geometry of water, i.e., excluding core-hole lifetime dynamics. The red traces show the spectra calculated incorporating the core-hole lifetime dynamics calculated using the MOM(DFT) method 66 for 1 (a), 2 (b), or 5 (c) GBFs. The short time of the dynamics (<10 fs) means that only a few GBFs are required.…”

Section: B Core-hole Dynamics Of Watermentioning

confidence: 99%

Non-equilibrium x-ray spectroscopy using direct quantum dynamics

Northey

Duffield

Penfold

2018

The Journal of Chemical Physics

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Advances in experimental methodology aligned with technological developments, such as 3rd generation light sources, X-ray Free Electron Lasers, and High Harmonic Generation, have led to a paradigm shift in the capability of X-ray spectroscopy to deliver high temporal and spectral resolution on an extremely broad range of samples in a wide array of different environments. Importantly, the complex nature and high information content of this class of techniques mean that detailed theoretical studies are often essential to provide a firm link between the spectroscopic observables and the underlying molecular structure and dynamics. In this paper, we present approaches for simulating dynamical processes in X-ray spectroscopy based upon on-the-fly quantum dynamics with a Gaussian basis set. We show that it is possible to provide a fully quantum description of X-ray spectra without the need of precomputing highly multidimensional potential energy surfaces. It is applied to study two different dynamical situations, namely, the core-hole lifetime dynamics of the water monomer and the dissociation of CF + 4 recently studied using pump-probe X-ray spectroscopy. Our results compare favourably to previous experiments, while reducing the computational effort, providing the scope to apply them to larger systems. https://doi.

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Simulation of Ultra-Fast Dynamics Effects in Resonant Inelastic X-ray Scattering of Gas-Phase Water

Cited by 18 publications

References 90 publications

Density Functional Theory Based Methods for the Calculation of X-ray Spectroscopy

Density Functional Theory Based Methods for the Calculation of X-ray Spectroscopy

Modeling of the spectroscopy of core electrons with density functional theory

Non-equilibrium x-ray spectroscopy using direct quantum dynamics

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