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Jiang S, Gudem M, Kowalewski M, Dorfman K. Multidimensional high-harmonic echo spectroscopy: Resolving coherent electron dynamics in the EUV regime. Proc Natl Acad Sci U S A 2024; 121:e2304821121. [PMID: 38315847 PMCID: PMC10873645 DOI: 10.1073/pnas.2304821121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Accepted: 12/18/2023] [Indexed: 02/07/2024] Open
Abstract
We theoretically propose a multidimensional high-harmonic echo spectroscopy technique which utilizes strong optical fields to resolve coherent electron dynamics spanning an energy range of multiple electronvolts. Using our recently developed semi-perturbative approach, we can describe the coherent valence electron dynamics driven by a sequence of phase-matched and well-separated short few-cycle strong infrared laser pulses. The recombination of tunnel-ionized electrons by each pulse coherently populates the valence states of a molecule, which allows for a direct observation of its dynamics via the high harmonic echo signal. The broad bandwidth of the effective dipole between valence states originated from the strong-field excitation results in nontrivial ultra-delayed partial rephasing echo, which is not observed in standard two-dimensional optical spectroscopic techniques in a two-level molecular systems. We demonstrate the results of simulations for the anionic molecular system and show that the ultrafast valence electron dynamics can be well captured with femtosecond resolution.
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Affiliation(s)
- Shicheng Jiang
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai200062, China
| | - Mahesh Gudem
- Department of Physics, Stockholm University, Albanova University Centre, StockholmSE-106 91, Sweden
| | - Markus Kowalewski
- Department of Physics, Stockholm University, Albanova University Centre, StockholmSE-106 91, Sweden
| | - Konstantin Dorfman
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai200062, China
- Center for Theoretical Physics and School of Sciences, Hainan University, Haikou570228, China
- Himalayan Institute for Advanced Study, Unit of Gopinath Seva Foundation, Rishikesh249201, India
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2
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Villaseco Arribas E, Maitra NT, Agostini F. Nonadiabatic dynamics with classical trajectories: The problem of an initial coherent superposition of electronic states. J Chem Phys 2024; 160:054102. [PMID: 38310471 DOI: 10.1063/5.0186984] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Accepted: 01/11/2024] [Indexed: 02/05/2024] Open
Abstract
Advances in coherent light sources and development of pump-probe techniques in recent decades have opened the way to study electronic motion in its natural time scale. When an ultrashort laser pulse interacts with a molecular target, a coherent superposition of electronic states is created and the triggered electron dynamics is coupled to the nuclear motion. A natural and computationally efficient choice to simulate this correlated dynamics is a trajectory-based method where the quantum-mechanical electronic evolution is coupled to a classical-like nuclear dynamics. These methods must approximate the initial correlated electron-nuclear state by associating an initial electronic wavefunction to each classical trajectory in the ensemble. Different possibilities exist that reproduce the initial populations of the exact molecular wavefunction when represented in a basis. We show that different choices yield different dynamics and explore the effect of this choice in Ehrenfest, surface hopping, and exact-factorization-based coupled-trajectory schemes in a one-dimensional two-electronic-state model system that can be solved numerically exactly. This work aims to clarify the problems that standard trajectory-based techniques might have when a coherent superposition of electronic states is created to initialize the dynamics, to discuss what properties and observables are affected by different choices of electronic initial conditions and to point out the importance of quantum-momentum-induced electronic transitions in coupled-trajectory schemes.
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Affiliation(s)
- Evaristo Villaseco Arribas
- Department of Physics, Rutgers University, Newark, New Jersey 07102, USA
- Université Paris-Saclay, CNRS, Institut de Chimie Physique UMR8000, 91405 Orsay, France
| | - Neepa T Maitra
- Department of Physics, Rutgers University, Newark, New Jersey 07102, USA
| | - Federica Agostini
- Université Paris-Saclay, CNRS, Institut de Chimie Physique UMR8000, 91405 Orsay, France
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Tolu D, Guillaumont D, de la Lande A. Irradiation of Plutonium Tributyl Phosphate Complexes by Ionizing Alpha Particles: A Computational Study. J Phys Chem A 2023; 127:7045-7057. [PMID: 37606197 DOI: 10.1021/acs.jpca.3c02117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/23/2023]
Abstract
The PUREX solvent extraction process, widely used for recovering uranium and plutonium from spent nuclear fuel, utilizes an organic solvent composed of tributyl phosphate (TBP). The emission of ionizing particles such as alpha particles, resulting from the decay of plutonium, makes the organic solvent vulnerable to degradation. Here, we study the ultrashort time alpha irradiation of tributylphosphate (TBP) and Pu(NO3)4(TBP)2 complex formed in the PUREX process. Electron dynamics is propagated by Real-Time-Dependent Auxiliary Density Functional Theory (RT-TD-ADFT). We investigate the use of previously proposed absorption boundary conditions (ABC) in the molecular orbital space to treat secondary electron emission. Basis set and exchange correlation functional effects with ABC are reported as well as a detailed analysis of the ABC parametrization. Preliminary results on the water molecule and then on TBP show that the phenomenological nature of the ABC parameters necessitates selecting appropriate values for each system under study. Irradiation of free and complexed TBP shows an influence of the ligands on the variation of atomic charges on the femtosecond time scale. An accumulation of atomic charges in the alkyl chains of TBP is observed in the case where the nitrate groups are predominantly irradiated. In addition, we find that the Pu atom regains its electric charge very rapidly after being hit by the projectile, with the coordination sphere serving as an electron reservoir to preserve its formal redox state. This study paves the road toward a full understanding of the degradation of organic extracants employed in the nuclear industry.
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Affiliation(s)
- Damien Tolu
- CEA, DES, ISEC, DMRC, Université Montpellier, Marcoule, 30207 Bagnols sur Cèze, France
- Institut de Chimie Physique, CNRS, Université Paris Saclay, 15 Avenue Jean Perrin, Paris, 91405, France
| | - Dominique Guillaumont
- CEA, DES, ISEC, DMRC, Université Montpellier, Marcoule, 30207 Bagnols sur Cèze, France
| | - Aurélien de la Lande
- Institut de Chimie Physique, CNRS, Université Paris Saclay, 15 Avenue Jean Perrin, Paris, 91405, France
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4
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Ruberti M, Patchkovskii S, Averbukh V. Quantum coherence in molecular photoionization. Phys Chem Chem Phys 2022; 24:19673-19686. [PMID: 35946491 DOI: 10.1039/d2cp01562e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The study of onset and decay, as well as control of ultrafast quantum coherence in many-electron systems is in the focus of interest of attosecond physics. Interpretation of attosecond experiments detecting the ultrafast quantum coherence requires application of advanced theoretical and computational tools combining many-electron theory, description of the electronic continuum, including in the strong laser field scenario, as well as nuclear dynamics theory. This perspective reviews the recent theoretical advances in understanding the attosecond dynamics of quantum coherence in photoionized molecular systems and outlines possible future directions of theoretical and experimental study of coherence and entanglement in the attosecond regime.
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Affiliation(s)
- Marco Ruberti
- Imperial College London, Department of Physics, South Kensington Campus, London SW7 2AZ, UK.
| | | | - Vitali Averbukh
- Imperial College London, Department of Physics, South Kensington Campus, London SW7 2AZ, UK.
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5
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Armstrong GSJ, Khokhlova MA, Labeye M, Maxwell AS, Pisanty E, Ruberti M. Dialogue on analytical and ab initio methods in attoscience. THE EUROPEAN PHYSICAL JOURNAL. D, ATOMIC, MOLECULAR, AND OPTICAL PHYSICS 2021; 75:209. [PMID: 34720730 PMCID: PMC8550504 DOI: 10.1140/epjd/s10053-021-00207-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Accepted: 06/18/2021] [Indexed: 06/13/2023]
Abstract
The perceived dichotomy between analytical and ab initio approaches to theory in attosecond science is often seen as a source of tension and misconceptions. This Topical Review compiles the discussions held during a round-table panel at the 'Quantum Battles in Attoscience' cecam virtual workshop, to explore the sources of tension and attempt to dispel them. We survey the main theoretical tools of attoscience-covering both analytical and numerical methods-and we examine common misconceptions, including the relationship between ab initio approaches and the broader numerical methods, as well as the role of numerical methods in 'analytical' techniques. We also evaluate the relative advantages and disadvantages of analytical as well as numerical and ab initio methods, together with their role in scientific discovery, told through the case studies of two representative attosecond processes: non-sequential double ionisation and resonant high-harmonic generation. We present the discussion in the form of a dialogue between two hypothetical theoreticians, a numericist and an analytician, who introduce and challenge the broader opinions expressed in the attoscience community.
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Affiliation(s)
- Gregory S. J. Armstrong
- Centre for Theoretical Atomic, Molecular, and Optical Physics, Queen’s University Belfast, Belfast, BT7 1NN UK
| | - Margarita A. Khokhlova
- Max Born Institute for Nonlinear Optics and Short Pulse Spectroscopy, Max-Born-Straße 2A, 12489 Berlin, Germany
- Department of Physics, Imperial College London, South Kensington Campus, London, SW7 2AZ UK
| | - Marie Labeye
- CNRS, PASTEUR, Département de chimie, Ecole Normale Supérieure, PSL University, Sorbonne Université, 75005 Paris, France
| | - Andrew S. Maxwell
- Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels (Barcelona), Spain
- Department of Physics and Astronomy, University College London, Gower Street, London, WC1E 6BT UK
| | - Emilio Pisanty
- Max Born Institute for Nonlinear Optics and Short Pulse Spectroscopy, Max-Born-Straße 2A, 12489 Berlin, Germany
- Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels (Barcelona), Spain
| | - Marco Ruberti
- Department of Physics, Imperial College London, South Kensington Campus, London, SW7 2AZ UK
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Ruberti M. Quantum electronic coherences by attosecond transient absorption spectroscopy: ab initio B-spline RCS-ADC study. Faraday Discuss 2021; 228:286-311. [PMID: 33575690 DOI: 10.1039/d0fd00104j] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Here I present a fully ab initio time-resolved study of X-ray attosecond transient absorption spectroscopy (ATAS) in a prototypical polyatomic molecule, pyrazine, and demonstrate the possibility of retrieving the many-electron quantum ionic coherences arising in attosecond molecular photoionisation and pre-determining the subsequent charge-directed photochemical reactivity. Advanced first-principles many-electron simulations are performed, within a hybrid XUV pump/X-ray probe setup, to describe the interaction of pyrazine with both XUV pump and X-ray probe pulses, and study the triggered correlated many-electron dynamics. The calculations are carried out by means of the recently-developed ab initio method for many-electron dynamics in polyatomic molecules, the time-dependent (TD) B-spline Restricted Correlation Space-Algebraic Diagrammatic Construction (RCS-ADC). RCS-ADC simulates molecular ionisation from first principles, combining the accurate description of electron correlation of quantum chemistry with the full account of the continuum dynamics of the photoelectron. Complete theoretical characterisation of the atto-ionised many-electron state and photo-induced attosecond charge dynamics is achieved by calculating the reduced ionic density matrix (R-IDM) of the bipartite ion-photoelectron system, with full inclusion of the correlated shakeup states. Deviations from the sudden approximation picture of photoionisation, in the low-photon-energy limit, are presented. The effect of the multi-channel interaction between the parent-ion and the emitted photoelectron on the onset of the quantum electronic coherences is analysed. Moreover, I show how the Schmidt decomposition of the R-IDM unravels the many-electron dynamics triggered by the pump, allowing for the identification of the key channels involved. Finally, I calculate the X-ray attosecond transient absorption spectra of XUV-ionised pyrazine. The results unveil the mapping of the ATAS measurement onto the quantum electronic coherences, and related non-zero R-IDM matrix elements, produced upon ionisation by the XUV pump laser pulse.
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Affiliation(s)
- M Ruberti
- Department of Physics, Imperial College London, Prince Consort Road, London SW7 2AZ, UK.
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7
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Vrakking MJJ. Control of Attosecond Entanglement and Coherence. PHYSICAL REVIEW LETTERS 2021; 126:113203. [PMID: 33798339 DOI: 10.1103/physrevlett.126.113203] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Accepted: 02/05/2021] [Indexed: 06/12/2023]
Abstract
Calculations are presented of vibrational wave packet dynamics in H_{2}^{+} ions formed by ionization of neutral H_{2} by a pair of attosecond extreme ultraviolet laser pulses, using time-delayed dissociation of the cation by an ultraviolet probe pulse. The strength of experimentally observable two-level quantum beats as a function of the attosecond two-pulse delay can be related to ion+photoelectron entanglement resulting from the ionization process. This conclusion is supported by an evaluation of the purity of the reduced ion and photoelectron density matrices.
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8
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Woźniak AP, Lesiuk M, Przybytek M, Efimov DK, Prauzner-Bechcicki JS, Mandrysz M, Ciappina M, Pisanty E, Zakrzewski J, Lewenstein M, Moszyński R. A systematic construction of Gaussian basis sets for the description of laser field ionization and high-harmonic generation. J Chem Phys 2021; 154:094111. [PMID: 33685145 DOI: 10.1063/5.0040879] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
A precise understanding of mechanisms governing the dynamics of electrons in atoms and molecules subjected to intense laser fields has a key importance for the description of attosecond processes such as the high-harmonic generation and ionization. From the theoretical point of view, this is still a challenging task, as new approaches to solve the time-dependent Schrödinger equation with both good accuracy and efficiency are still emerging. Until recently, the purely numerical methods of real-time propagation of the wavefunction using finite grids have been frequently and successfully used to capture the electron dynamics in small one- or two-electron systems. However, as the main focus of attoscience shifts toward many-electron systems, such techniques are no longer effective and need to be replaced by more approximate but computationally efficient ones. In this paper, we explore the increasingly popular method of expanding the wavefunction of the examined system into a linear combination of atomic orbitals and present a novel systematic scheme for constructing an optimal Gaussian basis set suitable for the description of excited and continuum atomic or molecular states. We analyze the performance of the proposed basis sets by carrying out a series of time-dependent configuration interaction calculations for the hydrogen atom in fields of intensity varying from 5 × 1013 W/cm2 to 5 × 1014 W/cm2. We also compare the results with the data obtained using Gaussian basis sets proposed previously by other authors.
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Affiliation(s)
| | - Michał Lesiuk
- Faculty of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw, Poland
| | - Michał Przybytek
- Faculty of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw, Poland
| | - Dmitry K Efimov
- Institute of Theoretical Physics, Jagiellonian University in Krakow, Łojasiewicza 11, 30-348 Kraków, Poland
| | - Jakub S Prauzner-Bechcicki
- Marian Smoluchowski Institute of Physics, Jagiellonian University in Krakow, Łojasiewicza 11, 30-348 Kraków, Poland
| | - Michał Mandrysz
- Institute of Theoretical Physics, Jagiellonian University in Krakow, Łojasiewicza 11, 30-348 Kraków, Poland
| | - Marcelo Ciappina
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, Av. Carl Friedrich Gauss 3, 08860, Castelldefels, Barcelona, Spain
| | - Emilio Pisanty
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, Av. Carl Friedrich Gauss 3, 08860, Castelldefels, Barcelona, Spain
| | - Jakub Zakrzewski
- Institute of Theoretical Physics, Jagiellonian University in Krakow, Łojasiewicza 11, 30-348 Kraków, Poland
| | - Maciej Lewenstein
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, Av. Carl Friedrich Gauss 3, 08860, Castelldefels, Barcelona, Spain
| | - Robert Moszyński
- Faculty of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw, Poland
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9
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Jiang S, Kowalewski M, Dorfman KE. Multi-wave mixing in the high harmonic regime: monitoring electronic dynamics. OPTICS EXPRESS 2021; 29:4746-4754. [PMID: 33726024 DOI: 10.1364/oe.414619] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Accepted: 01/18/2021] [Indexed: 06/12/2023]
Abstract
It has been demonstrated that electronic coherences across many eV can be detected in pump-probe experiments involving high harmonic sources. An additional degree of control over the phase matching can be employed by investigating a more general class of multi-wave mixing. Non-collinear multi-wave mixing of high harmonics with energy (q1ω1 + q2ω2) can be selectively detected along the direction of (q1k1 + q2k2). Simulations based on a recently developed semi-perturbative approach show that only the specific harmonic signals with q1ω1 close to the energy difference between ground state and excited states are observable when the two input pulses are well separated in time. The coherent dynamics between different states can be selectively tracked by detecting the time-delay dependent signals with different q1k1, which can overcome the potential spectral congestion in real experiments. Additionally, such non-collinear geometry can be used to separate the dephasing induced decay and collision induced recovery behaviors of pump-probe high harmonic signal typically observed in the time-resolved high harmonic pump-probe signals.
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10
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Jiang S, Dorfman K. Detecting electronic coherences by time-domain high-harmonic spectroscopy. Proc Natl Acad Sci U S A 2020; 117:9776-9781. [PMID: 32300011 PMCID: PMC7211971 DOI: 10.1073/pnas.1919360117] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Ultrafast spectroscopy is capable of monitoring electronic and vibrational states. For electronic states a few eV apart, an X-ray laser source is required. We propose an alternative method based on the time-domain high-order harmonic spectroscopy where a coherent superposition of the electronic states is first prepared by the strong optical laser pulse. The coherent dynamics can then be probed by the higher-order harmonics generated by the delayed probe pulse. The high nonlinearity typically modeled by the three-step mechanism introduced by Lewenstein and Corkum can serve as a recipe for generation of the coherent excitation with broad bandwidth. The main advantage of the method is that only optical (non-X-ray) lasers are needed. A semiperturbative model based on the Liouville space superoperator approach is developed for the bookkeeping of the different orders of the nonlinear response for the high-order harmonic generation using multiple pulses. Coherence between bound electronic states is monitored in the harmonic spectra from both first- and second-order responses.
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Affiliation(s)
- Shicheng Jiang
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062, China
| | - Konstantin Dorfman
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062, China
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11
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Cabral Tenorio BN, Chaer Nascimento MA, Rocha AB, Coriani S. Lanczos-based equation-of-motion coupled-cluster singles-and-doubles approach to the total photoionization cross section of valence excited states. J Chem Phys 2019; 151:184106. [DOI: 10.1063/1.5125125] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Bruno Nunes Cabral Tenorio
- Universidade Federal do Rio de Janeiro, UFRJ, Instituto de Química, Av. Athos da Silveira Ramos, 149, Rio de Janeiro, RJ 21941-909, Brazil
| | - Marco Antonio Chaer Nascimento
- Universidade Federal do Rio de Janeiro, UFRJ, Instituto de Química, Av. Athos da Silveira Ramos, 149, Rio de Janeiro, RJ 21941-909, Brazil
| | - Alexandre Braga Rocha
- Universidade Federal do Rio de Janeiro, UFRJ, Instituto de Química, Av. Athos da Silveira Ramos, 149, Rio de Janeiro, RJ 21941-909, Brazil
| | - Sonia Coriani
- DTU Chemistry, Technical University of Denmark, Kemitorvet, Building 207, DK-2800 Kongens Lyngby, Denmark
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12
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Yang L, Reimers JR, Kobayashi R, Hush NS. Competition between charge migration and charge transfer induced by nuclear motion following core ionization: Model systems and application to Li 2. J Chem Phys 2019; 151:124108. [PMID: 31575213 DOI: 10.1063/1.5117246] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Attosecond and femtosecond spectroscopies present opportunities for the control of chemical reaction dynamics and products, as well as for quantum information processing; we address the somewhat unique situation of core-ionization spectroscopy which, for dimeric chromophores, leads to strong valence charge localization and hence tightly paired potential-energy surfaces of very similar shape. Application is made to the quantum dynamics of core-ionized Li2 +. This system is chosen as Li2 is the simplest stable molecule facilitating both core ionization and valence ionization. First, the quantum dynamics of some model surfaces are considered, with the surprising result that subtle differences in shape between core-ionization paired surfaces can lead to dramatic differences in the interplay between electronic charge migration and charge transfer induced by nuclear motion. Then, equation-of-motion coupled-cluster calculations are applied to determine potential-energy surfaces for 8 core-excited state pairs, calculations believed to be the first of their type for other than the lowest-energy core-ionized molecular pair. While known results for the lowest-energy pair suggest that Li2 + is unsuitable for studying charge migration, higher-energy pairs are predicted to yield results showing competition between charge migration and charge transfer. Central is a focus on the application of Hush's 1975 theory for core-ionized X-ray photoelectron spectroscopy to understand the shapes of the potential-energy surfaces and hence predict key features of charge migration.
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Affiliation(s)
- Likun Yang
- International Centre for Quantum and Molecular Structures and Department of Physics, Shanghai University, Shanghai 200444, China
| | - Jeffrey R Reimers
- School of Mathematical and Physical Sciences, University of Technology Sydney, Sydney, NSW 2007, Australia
| | - Rika Kobayashi
- International Centre for Quantum and Molecular Structures and Department of Physics, Shanghai University, Shanghai 200444, China
| | - Noel S Hush
- School of Molecular Biosciences, The University of Sydney, Sydney, NSW 2006, Australia
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13
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Ruberti M. Onset of ionic coherence and ultrafast charge dynamics in attosecond molecular ionisation. Phys Chem Chem Phys 2019; 21:17584-17604. [PMID: 31372608 DOI: 10.1039/c9cp03074c] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Here is presented a fully ab initio theoretical framework for simulating the correlated many-electron dynamics occurring during and emerging from molecular ionisation by attosecond laser pulses. This is based on the time-dependent (TD) version of the B-spline restricted correlation space (RCS)-algebraic diagrammatic construction (ADC) method, with the full description of the photoelectron and inclusion of electron correlation effects, such as shakeup processes and inter-channel couplings. The nature of the ultrafast charge dynamics in the molecular ion is elucidated by quantitatively predicting the degree of electronic coherence and eigenstate content of the prepared molecular cationic state, beyond the commonly used sudden approximation. The results presented here for the acetylene and ethylene molecules show that even in the high photon energy regime the simulated hole dynamics is quantitatively different from the prediction of the sudden approximation. Moreover, for high-bandwidth ionising pulse, the residual interaction between the cation, in highly-excited shake-up states, and the emitted slow photoelectron gives rise to a loss of coherence in the ionic system which can persist for the first few femtoseconds after ionisation.
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Affiliation(s)
- M Ruberti
- Department of Physics, Imperial College London, Prince Consort Road, London SW7 2AZ, UK.
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14
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Ruberti M. Restricted Correlation Space B-Spline ADC Approach to Molecular Ionization: Theory and Applications to Total Photoionization Cross-Sections. J Chem Theory Comput 2019; 15:3635-3653. [PMID: 31136172 DOI: 10.1021/acs.jctc.9b00288] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Herein is presented a new approach to the ab initio algebraic diagrammatic construction (ADC) schemes for the polarization propagator, which is explicitly designed to accurately and efficiently describe molecular ionization. The restricted correlation space (RCS) version of the ADC methods up to second order of perturbation theory is derived via the intermediate state representation (ISR) and implemented in the multicenter B-spline basis set for the electronic continuum. Remarkably a general close-coupling structure of the RCS-ADC many-electron wave function, connecting the N-particle to the ( N - 1)-particle ADC intermediate states, emerges naturally as a nontrivial result of the RCS ansatz. Moreover, the introduced RCS-ADC schemes prove to be particularly manageable from a computational point of view, overcoming the practical limitations of the conventional ADC approaches. The quality of the new RCS-ADC( n) approaches is verified by performing a series of total photoionization cross-section calculations on a test set of molecules. The excellent agreement of the results with existing accurate benchmarks demonstrates that the RCS versions of the ADC schemes are optimal and quantitatively accurate methods for studying multichannel molecular photoionization.
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Affiliation(s)
- M Ruberti
- Department of Physics , Imperial College London , Prince Consort Road , London SW7 2AZ , United Kingdom
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15
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Perfetto E, Stefanucci G. CHEERS: a tool for correlated hole-electron evolution from real-time simulations. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2018; 30:465901. [PMID: 30359327 DOI: 10.1088/1361-648x/aae675] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We put forward a practical nonequilibrium Green's function (NEGF) scheme to perform real-time evolutions of many-body interacting systems driven out of equilibrium by external fields. CHEERS is a computational tool to solve the NEGF equation of motion in the so called generalized Kadanoff-Baym ansatz and it can be used for model systems as well as first-principles Hamiltonians. Dynamical correlation (or memory) effects are added to the Hartree-Fock dynamics through a many-body self-energy. Applications to time-dependent quantum transport, time-resolved photoabsorption and other ultrafast phenomena are discussed.
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Affiliation(s)
- E Perfetto
- CNR-ISM, Division of Ultrafast Processes in Materials (FLASHit), Area della ricerca di Roma 1, Monterotondo Scalo, Italy. Dipartimento di Fisica, Università di Roma Tor Vergata, Via della Ricerca Scientifica, 00133 Rome, Italy
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