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Littlejohn R, Rawlinson J, Subotnik J. Diagonalizing the Born-Oppenheimer Hamiltonian via Moyal perturbation theory, nonadiabatic corrections, and translational degrees of freedom. J Chem Phys 2024; 160:114103. [PMID: 38501907 DOI: 10.1063/5.0192465] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Accepted: 02/19/2024] [Indexed: 03/20/2024] Open
Abstract
This article describes a method for calculating higher order or nonadiabatic corrections in Born-Oppenheimer theory and its interaction with the translational degrees of freedom. The method uses the Wigner-Weyl correspondence to map nuclear operators into functions on the classical phase space and the Moyal star product to represent operator multiplication on those functions. These are explained in the body of the paper. The result is a power series in κ2, where κ = (m/M)1/4 is the usual Born-Oppenheimer parameter. The lowest order term is the usual Born-Oppenheimer approximation, while higher order terms are nonadiabatic corrections. These are needed in calculations of electronic currents, momenta, and densities. The separation of nuclear and electronic degrees of freedom takes place in the context of the exact symmetries (for an isolated molecule) of translations and rotations, and these, especially translations, are explicitly incorporated into our discussion. This article presents an independent derivation of the Moyal expansion in molecular Born-Oppenheimer theory. We show how electronic currents and momenta can be calculated within the framework of Moyal perturbation theory; we derive the transformation laws of the electronic Hamiltonian, the electronic eigenstates, and the derivative couplings under translations; we discuss in detail the rectilinear motion of the molecular center of mass in the Born-Oppenheimer representation; and we show how the elimination of the translational components of the derivative couplings leads to a unitary transformation that has the effect of exactly separating the translational degrees of freedom.
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Affiliation(s)
- Robert Littlejohn
- Department of Physics, University of California, Berkeley, California 94720, USA
| | - Jonathan Rawlinson
- School of Mathematics, University of Manchester, Manchester, United Kingdom
| | - Joseph Subotnik
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
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Schürger P, Engel V. Differential Shannon entropies and correlation measures for Born-Oppenheimer electron-nuclear dynamics: numerical results and their analytical interpretation. Phys Chem Chem Phys 2023; 25:28373-28381. [PMID: 37842823 DOI: 10.1039/d3cp03573e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2023]
Abstract
We study the Born-Oppenheimer dynamics within a model for a coupled electron-nuclear motion. Differential Shannon entropies are calculated from the time-dependent probability densities of the combined system and, using single particle densities, entropies for the electronic and nuclear degrees of freedom are derived. These functions provide information on details of the wave packet motion. From the entropies, we determine the mutual information which characterizes particle correlations. This quantity is compared to other measures of electron-nuclear entanglement. Numerical results are interpreted within an analytically solvable approach, and it is documented how these functions depend on properties of the Born-Oppenheimer wave function and, in particular, how dynamical effects like wave packet focusing and dispersion influence the correlation between the particles.
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Affiliation(s)
- Peter Schürger
- Universität Würzburg, Institut für Physikalische und Theoretische Chemie, Emil-Fischer-Str. 42, 97074 Würzburg, Germany.
| | - Volker Engel
- Universität Würzburg, Institut für Physikalische und Theoretische Chemie, Emil-Fischer-Str. 42, 97074 Würzburg, Germany.
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Schürger P, Engel V. Differential Shannon Entropies Characterizing Electron-Nuclear Dynamics and Correlation: Momentum-Space Versus Coordinate-Space Wave Packet Motion. ENTROPY (BASEL, SWITZERLAND) 2023; 25:970. [PMID: 37509917 PMCID: PMC10378028 DOI: 10.3390/e25070970] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Revised: 06/15/2023] [Accepted: 06/20/2023] [Indexed: 07/30/2023]
Abstract
We calculate differential Shannon entropies derived from time-dependent coordinate-space and momentum-space probability densities. This is performed for a prototype system of a coupled electron-nuclear motion. Two situations are considered, where one is a Born-Oppenheimer adiabatic dynamics, and the other is a diabatic motion involving strong non-adiabatic transitions. The information about coordinate- and momentum-space dynamics derived from the total and single-particle entropies is discussed and interpreted with the help of analytical models. From the entropies, we derive mutual information, which is a measure for the electron-nuclear correlation. In the adiabatic case, it is found that such correlations are manifested differently in coordinate- and momentum space. For the diabatic dynamics, we show that it is possible to decompose the entropies into state-specific contributions.
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Affiliation(s)
- Peter Schürger
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Emil-Fischer-Str. 42, 97074 Würzburg, Germany
| | - Volker Engel
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Emil-Fischer-Str. 42, 97074 Würzburg, Germany
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Ivanova B, Spiteller M. Stochastic dynamic ultraviolet photofragmentation and high collision energy dissociation mass spectrometric kinetics of triadimenol and sucralose. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:32348-32370. [PMID: 36462070 DOI: 10.1007/s11356-022-24259-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Accepted: 11/13/2022] [Indexed: 06/17/2023]
Abstract
The major goal of the paper is to provide empirical proof of view that innovative stochastic dynamic mass spectrometric equation D″SD = 2.6388·10-17·(< I2 > - < I > 2) determines the exact analyte concentration in solution via quantifying experimental variable intensity (I) of an analyte ion per any short span of scan time of any measurement, which also appears applicable to quantify laser-induced ultraviolet photofragmentation and high energy collision dissociation mass spectrometric processes. Triadimenol (1) and sucralose (2) using positive and negative polarity are examined. Laser irradiation energy λex = 213 nm is utilized. The issue is of central importance for monitoring organic micro-pollutants in surface, ground, and drinking water as well as tasks of risk assessment for environment and human health from contamination with organics. Despite the significant importance of the topic, answering the question of functional kinetic relations of such processes is by no means straightforward, so far, due to a lack of in-depth knowledge of mechanistic aspects of fragment paths of analytes in environment and foods as well as kinetics of processes under ultraviolet laser irradiation. Although there is truth in the classical theory of first-order reaction kinetics, it does not describe all kinetic data on analytes (1) and (2). A new damped sine wave functional response to a large amount of kinetics is presented. High-resolution mass spectrometric data and chemometrics are used. The study provides empirical evidence for claim that temporal behavior of mass spectrometric variable intensity under negative polarity obeys a certain scientific law written by means of equation above. It is the same for positive and negative soft-ionization mass spectrometric conditions.
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Affiliation(s)
- Bojidarka Ivanova
- Lehrstuhl Für Analytische Chemie, Institut Für Umweltforschung, Fakultät Für Chemie Und Chemische Biologie, Universität Dortmund, Otto-Hahn-Straße 6, 44221, Dortmund, Nordrhein-Westfalen, Germany.
| | - Michael Spiteller
- Lehrstuhl Für Analytische Chemie, Institut Für Umweltforschung, Fakultät Für Chemie Und Chemische Biologie, Universität Dortmund, Otto-Hahn-Straße 6, 44221, Dortmund, Nordrhein-Westfalen, Germany
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Schürger P, Renziehausen K, Schaupp T, Barth I, Engel V. Time-Dependent Expectation Values from Integral Equations for Quantum Flux and Probability Densities. J Phys Chem A 2022; 126:8964-8975. [DOI: 10.1021/acs.jpca.2c05995] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- P. Schürger
- Institut für Physikalische und Theoretische Chemie, Universität Würzburg, Emil-Fischer-Strasse 42, 97074 Würzburg, Germany
| | - K. Renziehausen
- Friedrich Schiller University Jena, Helmholtzweg 4, 07743 Jena, Germany
- Theory Department, Max-Planck-Institute of Microstructure Physics, Weinberg 2, 06120 Halle (Saale), Germany
| | - T. Schaupp
- Institut für Physikalische und Theoretische Chemie, Universität Würzburg, Emil-Fischer-Strasse 42, 97074 Würzburg, Germany
| | - I. Barth
- Theory Department, Max-Planck-Institute of Microstructure Physics, Weinberg 2, 06120 Halle (Saale), Germany
| | - V. Engel
- Institut für Physikalische und Theoretische Chemie, Universität Würzburg, Emil-Fischer-Strasse 42, 97074 Würzburg, Germany
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Ziems KM, Bruhnke J, Engel V, Gräfe S. Nuclear–Electron Correlation Effects and Their Photoelectron Imprint in Molecular XUV Ionisation. Front Chem 2022; 10:942633. [PMID: 35991602 PMCID: PMC9388718 DOI: 10.3389/fchem.2022.942633] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Accepted: 06/20/2022] [Indexed: 11/29/2022] Open
Abstract
The ionisation of molecules by attosecond XUV pulses is accompanied by complex correlated dynamics, such as the creation of coherent electron wave packets in the parent ion, their interplay with nuclear wave packets, and a correlated photoelectron moving in a multi-centred potential. Additionally, these processes are influenced by the dynamics prior to and during the ionisation. To fully understand and subsequently control the ionisation process on different time scales, a profound understanding of electron and nuclear correlation is needed. Here, we investigate the effect of nuclear–electron correlation in a correlated two-electron and one-nucleus quantum model system. Solving the time-dependent Schrödinger equation allows to monitor the correlation impact pre, during, and post-XUV ionisation. We show how an initial nuclear wave packet displaced from equilibrium influences the post-ionisation dynamics by means of momentum conservation between the target and parent ion, whilst the attosecond electron population remains largely unaffected. We calculate time-resolved photoelectron spectra and their asymmetries and demonstrate how the coupled electron–nuclear dynamics are imprinted on top of electron–electron correlation on the photoelectron properties. Finally, our findings give guidelines towards when correlation resulting effects have to be incorporated and in which instances the exact correlation treatment can be neglected.
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Affiliation(s)
- Karl Michael Ziems
- Institute of Physical Chemistry, Friedrich Schiller University Jena, Jena, Germany
- Max Planck School of Photonics, Jena, Germany
| | - Jakob Bruhnke
- Institute of Physical Chemistry, Friedrich Schiller University Jena, Jena, Germany
| | - Volker Engel
- Institut für Physikalische und Theoretische Chemie, Universität Würzburg, Würzburg, Germany
| | - Stefanie Gräfe
- Institute of Physical Chemistry, Friedrich Schiller University Jena, Jena, Germany
- Max Planck School of Photonics, Jena, Germany
- Abbe Center of Photonics, Friedrich Schiller University, Jena, Germany
- Fraunhofer Institute for Applied Optics and Precision Engineering, Jena, Germany
- *Correspondence: Stefanie Gräfe,
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