1
|
Neupane P, Bartels DM, Thompson WH. Empirically Optimized One-Electron Pseudopotential for the Hydrated Electron: A Proof-of-Concept Study. J Phys Chem B 2023; 127:7361-7371. [PMID: 37556737 DOI: 10.1021/acs.jpcb.3c03540] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/11/2023]
Abstract
Mixed quantum-classical molecular dynamics simulations have been important tools for studying the hydrated electron. They generally use a one-electron pseudopotential to describe the interactions of an electron with the water molecules. This approximation shows both the strength and weakness of the approach. On the one hand, it enables extensive statistical sampling and large system sizes that are not possible with more accurate ab initio molecular dynamics methods. On the other hand, there has (justifiably) been much debate about the ability of pseudopotentials to accurately and quantitatively describe the hydrated electron properties. These pseudopotentials have largely been derived by fitting them to ab initio calculations of an electron interacting with a single water molecule. In this paper, we present a proof-of-concept demonstration of an alternative approach in which the pseudopotential parameters are determined by optimizing them to reproduce key experimental properties. Specifically, we develop a new pseudopotential, using the existing TBOpt model as a starting point, which correctly describes the hydrated electron vertical detachment energy and radius of gyration. In addition to these properties, this empirically optimized model displays a significantly modified solvation structure, which improves, for example, the prediction of the partial molar volume.
Collapse
Affiliation(s)
- Pauf Neupane
- Department of Chemistry, University of Kansas, Lawrence, Kansas 66045, United States
| | - David M Bartels
- Radiation Laboratory, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Ward H Thompson
- Department of Chemistry, University of Kansas, Lawrence, Kansas 66045, United States
| |
Collapse
|
2
|
Lan J, Rybkin VV, Pasquarello A. Temperature Dependent Properties of the Aqueous Electron. Angew Chem Int Ed Engl 2022; 61:e202209398. [PMID: 35849110 PMCID: PMC9541610 DOI: 10.1002/anie.202209398] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Indexed: 11/07/2022]
Abstract
The temperature‐dependent properties of the aqueous electron have been extensively studied using mixed quantum‐classical simulations in a wide range of thermodynamic conditions based on one‐electron pseudopotentials. While the cavity model appears to explain most of the physical properties of the aqueous electron, only a non‐cavity model has so far been successful in accounting for the temperature dependence of the absorption spectrum. Here, we present an accurate and efficient description of the aqueous electron under various thermodynamic conditions by combining hybrid functional‐based molecular dynamics, machine learning techniques, and multiple time‐step methods. Our advanced simulations accurately describe the temperature dependence of the absorption maximum in the presence of cavity formation. Specifically, our work reveals that the red shift of the absorption maximum results from an increasing gyration radius with temperature, rather than from global density variations as previously suggested.
Collapse
Affiliation(s)
- Jinggang Lan
- Chaire de Simulation àl'Echelle Atomique (CSEA)Ecole Polytechnique Fédérale de Lausanne (EPFL)CH-1015LausanneSwitzerland
| | | | - Alfredo Pasquarello
- Chaire de Simulation àl'Echelle Atomique (CSEA)Ecole Polytechnique Fédérale de Lausanne (EPFL)CH-1015LausanneSwitzerland
| |
Collapse
|
3
|
Lan J, Rybkin VV, Pasquarello A. Temperature Dependent Properties of the Aqueous Electron. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202209398] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Jinggang Lan
- EPFL: Ecole Polytechnique Federale de Lausanne Chaire de Simulation à l’Echelle Atomique 1015 Lausanne SWITZERLAND
| | | | - Alfredo Pasquarello
- EPFL: Ecole Polytechnique Federale de Lausanne Chaire de Simulation à l’Echelle Atomique SWITZERLAND
| |
Collapse
|
4
|
Park SJ, Schwartz BJ. Understanding the Temperature Dependence and Finite Size Effects in Ab Initio MD Simulations of the Hydrated Electron. J Chem Theory Comput 2022; 18:4973-4982. [PMID: 35834750 DOI: 10.1021/acs.jctc.2c00335] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The hydrated electron is of interest to both theorists and experimentalists as a paradigm solution-phase quantum system. Although the bulk of the theoretical work studying the hydrated electron is based on mixed quantum/classical (MQC) methods, recent advances in computer power have allowed several attempts to study this object using ab initio methods. The difficulty with employing ab initio methods for this system is that even with relatively inexpensive quantum chemistry methods such as density functional theory (DFT), such calculations are still limited to at most a few tens of water molecules and only a few picoseconds duration, leaving open the question as to whether the calculations are converged with respect to either system size or dynamical fluctuations. Moreover, the ab initio simulations of the hydrated electron that have been published to date have provided only limited analysis. Most works calculate the electron's vertical detachment energy, which can be compared to experiment, and occasionally the electronic absorption spectrum is also computed. Structural features, such as pair distribution functions, are rare in the literature, with the majority of the structural analysis being simple statements that the electron resides in a cavity, which are often based only on a small number of simulation snapshots. Importantly, there has been no ab initio work examining the temperature-dependent behavior of the hydrated electron, which has not been satisfactorily explained by MQC simulations. In this work, we attempt to remedy this situation by running DFT-based ab initio simulations of the hydrated electron as a function of both box size and temperature. We show that the calculated properties of the hydrated electron are not converged even with simulation sizes up to 128 water molecules and durations of several tens of picoseconds. The simulations show significant changes in the water coordination and solvation structure with box size. Our temperature-dependent simulations predict a red-shift of the absorption spectrum (computed using TD-DFT with an optimally tuned range-separated hybrid functional) with increasing temperature, but the magnitude of the predicted red-shift is larger than that observed experimentally, and the absolute position of the calculated spectra are off by over half an eV. The spectral red-shift at high temperatures is accompanied by both a partial loss of structure of the electron's central cavity and an increased radius of gyration that pushes electron density onto and beyond the first solvation shell. Overall, although ab initio simulations can provide some insights into the temperature-dependent behavior of the hydrated electron, the simulation sizes and level of quantum chemistry theory that are currently accessible are inadequate for correctly describing the experimental properties of this fascinating object.
Collapse
Affiliation(s)
- Sanghyun J Park
- Department of Chemistry and Biochemistry University of California,Los Angeles Los Angeles California 90095-1569, United States
| | - Benjamin J Schwartz
- Department of Chemistry and Biochemistry University of California,Los Angeles Los Angeles California 90095-1569, United States
| |
Collapse
|
5
|
Omar KA, Hasnaoui K, de la Lande A. First-Principles Simulations of Biological Molecules Subjected to Ionizing Radiation. Annu Rev Phys Chem 2021; 72:445-465. [PMID: 33878897 DOI: 10.1146/annurev-physchem-101419-013639] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Ionizing rays cause damage to genomes, proteins, and signaling pathways that normally regulate cell activity, with harmful consequences such as accelerated aging, tumors, and cancers but also with beneficial effects in the context of radiotherapies. While the great pace of research in the twentieth century led to the identification of the molecular mechanisms for chemical lesions on the building blocks of biomacromolecules, the last two decades have brought renewed questions, for example, regarding the formation of clustered damage or the rich chemistry involving the secondary electrons produced by radiolysis. Radiation chemistry is now meeting attosecond science, providing extraordinary opportunities to unravel the very first stages of biological matter radiolysis. This review provides an overview of the recent progress made in this direction, focusing mainly on the atto- to femto- to picosecond timescales. We review promising applications of time-dependent density functional theory in this context.
Collapse
Affiliation(s)
- Karwan Ali Omar
- Institut de Chimie Physique, CNRS UMR 8000, Université Paris-Saclay, 91405 Orsay, France; .,Department of Chemistry, College of Education, University of Sulaimani, 41005 Kurdistan, Iraq
| | - Karim Hasnaoui
- High Performance Computing User Support Team, Institut du Développement et des Ressources en Informatique Scientifique (IDRIS), 91403 Orsay, France.,Maison de la Simulation, CNRS, Commissariat à l'Energie Atomique et aux Énergies Alternatives (CEA), Université Paris-Saclay, 91191 Gif-sur-Yvette, France
| | - Aurélien de la Lande
- Institut de Chimie Physique, CNRS UMR 8000, Université Paris-Saclay, 91405 Orsay, France;
| |
Collapse
|
6
|
Glover WJ, Schwartz BJ. The Fluxional Nature of the Hydrated Electron: Energy and Entropy Contributions to Aqueous Electron Free Energies. J Chem Theory Comput 2020; 16:1263-1270. [PMID: 31914315 DOI: 10.1021/acs.jctc.9b00496] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
There has been a great deal of recent controversy over the structure of the hydrated electron and whether it occupies a cavity or contains a significant number of interior waters (noncavity). The questions we address in this work are, from a free energy perspective, how different are these proposed structures? Do the different structures all lie along a single continuum, or are there significant differences (i.e., free energy barriers) between them? To address these questions, we have performed a series of one-electron calculations using umbrella sampling with quantum biased molecular dynamics along a coordinate that directly reflects the number of water molecules in the hydrated electron's interior. We verify that a standard cavity model of the hydrated electron behaves essentially as a hard sphere: the model is dominated by repulsion at short range such that water is expelled from a local volume around the electron, leading to a water solvation shell like that of a pseudohalide ion. The repulsion is much larger than thermal energies near room temperature, explaining why such models exhibit properties with little temperature dependence. On the other hand, our calculations reveal that a noncavity model is highly fluxional, meaning that thermal motions cause the number of interior waters to fluctuate from effectively zero (i.e., a cavity-type electron) to potentially above the bulk water density. The energetic contributions in the noncavity model are still repulsive in the sense that they favor cavity formation, so the fluctuations in structure are driven largely by entropy: the entropic cost for expelling water from a region of space is large enough that some water is still driven into the electron's interior. As the temperature is lowered and entropy becomes less important, the noncavity electron's structure is predicted to become more cavity-like, consistent with the observed temperature dependence of the hydrated electron's properties. Thus, we argue that although the specific noncavity model we study overestimates the preponderance of fluctuations involving interior water molecules, with appropriate refinements to correctly capture the true average number of interior waters and molar solvation volume, a fluxional model likely makes the most sense for understanding the various experimental properties of the hydrated electron.
Collapse
Affiliation(s)
- William J Glover
- NYU Shanghai , 1555 Century Ave. , Pudong, Shanghai , China 200122.,NYU-ECNU Center for Computational Chemistry at NYU Shanghai , 3663 Zhongshang Road , Shanghai , China 200062.,Department of Chemistry , New York University , New York , New York 10003 , United States
| | - Benjamin J Schwartz
- Department of Chemistry and Biochemistry , University of California, Los Angeles , 607 Charles E. Young Drive East , Los Angeles , California 90095-1569 , United States
| |
Collapse
|
7
|
Structure and spectrum of the hydrated electron. A combined quantum chemical statistical mechanical simulation. J Mol Liq 2019. [DOI: 10.1016/j.molliq.2019.111300] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
|
8
|
Affiliation(s)
- Kazuo Kobayashi
- The Institute of Scientific and Industrial Research, Osaka University, Mihogaoka 8-1, Ibaraki, Osaka 567-0047, Japan
| |
Collapse
|
9
|
Abstract
A cavity or excluded-volume structure best explains the experimental properties of the aqueous or “hydrated” electron.
Collapse
Affiliation(s)
- John M. Herbert
- Department of Chemistry & Biochemistry
- The Ohio State University
- Columbus
- USA
| |
Collapse
|
10
|
Wang F, Archirel P, Muroya Y, Yamashita S, Pernot P, Yin C, El Omar AK, Schmidhammer U, Teuler JM, Mostafavi M. Effect of the solvation state of electron in dissociative electron attachment reaction in aqueous solutions. Phys Chem Chem Phys 2018; 19:23068-23077. [PMID: 28817148 DOI: 10.1039/c7cp03997b] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
It is generally considered that the pre-solvated electron and the solvated electron reacting with a solute yield the same product. Silver cyanide complex, Ag(CN)2-, is used as a simple probe to demonstrate unambiguously the existence of a different reduction mechanism for pre-hydrated electrons. Using systematic multichannel transient absorption measurements at different solute concentrations from millimolar to decimolar, global data analysis and theoretical calculations, we present the dissociative electron attachment on Ag(CN)2-. The short-lived silver complex, Ag0(CN)22-, formed by hydrated electron with nanosecond pulse radiolysis, can be observed at room temperature. However, at higher temperatures only the free silver atom, Ag0, is detected, suggesting that Ag0(CN)22- dissociation is fast. Surprisingly, pulse radiolysis measurements on Ag(CN)2- reduction, performed by a 7 ps electron pulse at room temperature, show clearly that a new reduced form of silver complex, AgCN-, is produced within the pulse. This species, absorbing at 560 nm, is not formed by the hydrated electron but exclusively by its precursor. DFT calculations show that the different reactivity of the hydrated and pre-hydrated electrons can be due to the formation of different electronic states of Ag0(CN)22-: the prehydrated electron can form an excited state of this complex, which mainly dissociates into Ag0CN- + CN-.
Collapse
Affiliation(s)
- Furong Wang
- Laboratoire de Chimie Physique, UMR 8000 CNRS/Université Paris-Sud, Bât. 349, Orsay, 91405, Cedex, France.
| | - Pierre Archirel
- Laboratoire de Chimie Physique, UMR 8000 CNRS/Université Paris-Sud, Bât. 349, Orsay, 91405, Cedex, France.
| | - Yusa Muroya
- Department of Beam Materials Science, Institute of Scientific and Industrial Research, Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka 567-0047, Japan
| | - Shinichi Yamashita
- Nuclear Professional School, School of Engineering, The University of Tokyo, 2-22 Shirakata Shirane, Tokai-mura, Naka-gun, Ibaraki 319-1188, Japan
| | - Pascal Pernot
- Laboratoire de Chimie Physique, UMR 8000 CNRS/Université Paris-Sud, Bât. 349, Orsay, 91405, Cedex, France.
| | - Chengying Yin
- Laboratoire de Chimie Physique, UMR 8000 CNRS/Université Paris-Sud, Bât. 349, Orsay, 91405, Cedex, France.
| | - Abdel Karim El Omar
- Laboratoire de Physique et Modélisation, Ecole Doctorale des Sciences et de Technologie, Lebanese University, Tripoli, Lebanon
| | - Uli Schmidhammer
- Laboratoire de Chimie Physique, UMR 8000 CNRS/Université Paris-Sud, Bât. 349, Orsay, 91405, Cedex, France.
| | - Jean-Marie Teuler
- Laboratoire de Chimie Physique, UMR 8000 CNRS/Université Paris-Sud, Bât. 349, Orsay, 91405, Cedex, France.
| | - Mehran Mostafavi
- Laboratoire de Chimie Physique, UMR 8000 CNRS/Université Paris-Sud, Bât. 349, Orsay, 91405, Cedex, France.
| |
Collapse
|
11
|
Zho CC, Farr EP, Glover WJ, Schwartz BJ. Temperature dependence of the hydrated electron’s excited-state relaxation. I. Simulation predictions of resonance Raman and pump-probe transient absorption spectra of cavity and non-cavity models. J Chem Phys 2017; 147:074503. [DOI: 10.1063/1.4985905] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Affiliation(s)
- Chen-Chen Zho
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California,
90095-1569, USA
| | - Erik P. Farr
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California,
90095-1569, USA
| | - William J. Glover
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California,
90095-1569, USA
- NYU-ECNU Center for Computational Chemistry at NYU Shanghai, Shanghai 200062, China
- NYU Shanghai, 1555 Century Avenue,
Shanghai 200135, China
| | - Benjamin J. Schwartz
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California,
90095-1569, USA
| |
Collapse
|
12
|
Ma J, Archirel P, Pernot P, Schmidhammer U, Le Caër S, Mostafavi M. Identification of Transient Radical Anions (LiClO4)n– (n = 1–3) in THF Solutions: Experimental and Theoretical Investigation on Electron Localization in Oligomers. J Phys Chem B 2016; 120:773-84. [DOI: 10.1021/acs.jpcb.5b11315] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Jun Ma
- Laboratoire de
Chimie Physique/ELYSE, UMR 8000, CNRS/Univ. Paris-Sud, Bât. 349, 91405 Orsay, Cedex, France
| | - Pierre Archirel
- Laboratoire de
Chimie Physique/ELYSE, UMR 8000, CNRS/Univ. Paris-Sud, Bât. 349, 91405 Orsay, Cedex, France
| | - Pascal Pernot
- Laboratoire de
Chimie Physique/ELYSE, UMR 8000, CNRS/Univ. Paris-Sud, Bât. 349, 91405 Orsay, Cedex, France
| | - Uli Schmidhammer
- Laboratoire de
Chimie Physique/ELYSE, UMR 8000, CNRS/Univ. Paris-Sud, Bât. 349, 91405 Orsay, Cedex, France
| | - Sophie Le Caër
- CEA/Saclay,
DSM/IRAMIS/NIMBE
UMR 3685/LIONS, Bât. 546, F-91191 Gif-sur-Yvette, Cedex, France
| | - Mehran Mostafavi
- Laboratoire de
Chimie Physique/ELYSE, UMR 8000, CNRS/Univ. Paris-Sud, Bât. 349, 91405 Orsay, Cedex, France
| |
Collapse
|
13
|
Dale SG, Johnson ER. Counterintuitive electron localisation from density-functional theory with polarisable solvent models. J Chem Phys 2015; 143:184112. [DOI: 10.1063/1.4935177] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
|
14
|
Swiatla-Wojcik D. Water-structure based mechanistic view on the bimolecular decay of the hydrated electron. Chem Phys Lett 2015. [DOI: 10.1016/j.cplett.2015.10.046] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
15
|
Urbanek J, Vöhringer P. Below-Band-Gap Ionization of Liquid-to-Supercritical Ammonia: Geminate Recombination via Proton-Coupled Back Electron Transfer. J Phys Chem B 2013; 118:265-77. [DOI: 10.1021/jp4103993] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Janus Urbanek
- Abteilung für Molekulare
Physikalische Chemie, Institut für Physikalische und Theoretische
Chemie, Rheinische Friedrich-Wilhelms-Universität, Wegelerstraße 12, 53115 Bonn, Germany
| | - Peter Vöhringer
- Abteilung für Molekulare
Physikalische Chemie, Institut für Physikalische und Theoretische
Chemie, Rheinische Friedrich-Wilhelms-Universität, Wegelerstraße 12, 53115 Bonn, Germany
| |
Collapse
|
16
|
Ma J, Archirel P, Schmidhammer U, Teuler JM, Pernot P, Mostafavi M. Reduction of Earth Alkaline Metal Salts in THF Solution Studied by Picosecond Pulse Radiolysis. J Phys Chem A 2013; 117:14048-55. [DOI: 10.1021/jp410598y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Affiliation(s)
- Jun Ma
- Laboratoire
de Chimie Physique/ELYSE, CNRS/Université Paris-Sud, Faculté des Sciences d’Orsay, Bât. 349, 91405 Orsay Cedex, France
| | - Pierre Archirel
- Laboratoire
de Chimie Physique/ELYSE, CNRS/Université Paris-Sud, Faculté des Sciences d’Orsay, Bât. 349, 91405 Orsay Cedex, France
| | - Uli Schmidhammer
- Laboratoire
de Chimie Physique/ELYSE, CNRS/Université Paris-Sud, Faculté des Sciences d’Orsay, Bât. 349, 91405 Orsay Cedex, France
| | - Jean-Marie Teuler
- Laboratoire
de Chimie Physique/ELYSE, CNRS/Université Paris-Sud, Faculté des Sciences d’Orsay, Bât. 349, 91405 Orsay Cedex, France
| | - Pascal Pernot
- Laboratoire
de Chimie Physique/ELYSE, CNRS/Université Paris-Sud, Faculté des Sciences d’Orsay, Bât. 349, 91405 Orsay Cedex, France
| | - Mehran Mostafavi
- Laboratoire
de Chimie Physique/ELYSE, CNRS/Université Paris-Sud, Faculté des Sciences d’Orsay, Bât. 349, 91405 Orsay Cedex, France
| |
Collapse
|
17
|
Melicherčík M, Pitoňák M, Kellö V, Hobza P, Neogrády P. Off-Center Gaussian Functions, an Alternative Atomic Orbital Basis Set for Accurate Noncovalent Interaction Calculations of Large Systems. J Chem Theory Comput 2013; 9:5296-304. [DOI: 10.1021/ct400692b] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Miroslav Melicherčík
- Department
of Computer Science, Faculty of Natural Sciences, Matej Bel University, Tajovského 40, 974 01 Banská Bystrica, Slovakia
| | - Michal Pitoňák
- Department
of Physical and Theoretical Chemistry, Faculty of Natural Sciences, Comenius University, Mlynská Dolina, 842 15 Bratislava, Slovakia
- Computing
Center of the Slovak Academy of Sciences, Dúbravská cesta č. 9, 845 35 Bratislava, Slovakia
| | - Vladimír Kellö
- Department
of Physical and Theoretical Chemistry, Faculty of Natural Sciences, Comenius University, Mlynská Dolina, 842 15 Bratislava, Slovakia
| | - Pavel Hobza
- Institute of Organic Chemistry and Biochemistry, Academy
of Sciences of the Czech Republic, v. v. i., Flemingovo nám. 2, 166 10 Praha 6, Czech Republic
- Department
of Physical Chemistry, Palacký University, 771 46 Olomouc, Czech Republic
| | - Pavel Neogrády
- Department
of Physical and Theoretical Chemistry, Faculty of Natural Sciences, Comenius University, Mlynská Dolina, 842 15 Bratislava, Slovakia
| |
Collapse
|
18
|
Resonance Raman and temperature-dependent electronic absorption spectra of cavity and noncavity models of the hydrated electron. Proc Natl Acad Sci U S A 2013; 110:2712-7. [PMID: 23382233 DOI: 10.1073/pnas.1219438110] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Most of what is known about the structure of the hydrated electron comes from mixed quantum/classical simulations, which depend on the pseudopotential that couples the quantum electron to the classical water molecules. These potentials usually are highly repulsive, producing cavity-bound hydrated electrons that break the local water H-bonding structure. However, we recently developed a more attractive potential, which produces a hydrated electron that encompasses a region of enhanced water density. Both our noncavity and the various cavity models predict similar experimental observables. In this paper, we work to distinguish between these models by studying both the temperature dependence of the optical absorption spectrum, which provides insight into the balance of the attractive and repulsive terms in the potential, and the resonance Raman spectrum, which provides a direct measure of the local H-bonding environment near the electron. We find that only our noncavity model can capture the experimental red shift of the hydrated electron's absorption spectrum with increasing temperature at constant density. Cavity models of the hydrated electron predict a solvation structure similar to that of the larger aqueous halides, leading to a Raman O-H stretching band that is blue-shifted and narrower than that of bulk water. In contrast, experiments show the hydrated electron has a broader and red-shifted O-H stretching band compared with bulk water, a feature recovered by our noncavity model. We conclude that although our noncavity model does not provide perfect quantitative agreement with experiment, the hydrated electron must have a significant degree of noncavity character.
Collapse
|
19
|
Turi L, Rossky PJ. Theoretical studies of spectroscopy and dynamics of hydrated electrons. Chem Rev 2012; 112:5641-74. [PMID: 22954423 DOI: 10.1021/cr300144z] [Citation(s) in RCA: 129] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- László Turi
- Department of Physical Chemistry, Eötvös Loránd University, Budapest, Hungary.
| | | |
Collapse
|
20
|
Marsalek O, Uhlig F, VandeVondele J, Jungwirth P. Structure, dynamics, and reactivity of hydrated electrons by ab initio molecular dynamics. Acc Chem Res 2012; 45:23-32. [PMID: 21899274 DOI: 10.1021/ar200062m] [Citation(s) in RCA: 77] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Understanding the properties of hydrated electrons, which were first observed using pulse radiolysis of water in 1962, is crucial because they are key species in many radiation chemistry processes. Although time-resolved spectroscopic studies and molecular simulations have shown that an electron in water (prepared, for example, by water photoionization) relaxes quickly to a localized, cavity-like structure ∼2.5 Å in radius, this picture has recently been questioned. In another experimental approach, negatively charged water clusters of increasing size were studied with photoelectron and IR spectroscopies. Although small water clusters can bind an excess electron, their character is very different from bulk hydrated species. As data on electron binding in liquid water have become directly accessible experimentally, the cluster-to-bulk extrapolations have become a topic of lively debate. Quantum electronic structure calculations addressing experimental measurables have, until recently, been largely limited to small clusters; extended systems were approached mainly with pseudopotential calculations combining a classical description of water with a quantum mechanical treatment of the excess electron. In this Account, we discuss our investigations of electrons solvated in water by means of ab initio molecular dynamics simulations. This approach, applied to a model system of a negatively charged cluster of 32 water molecules, allows us to characterize structural, dynamical, and reactive aspects of the hydrated electron using all of the system's valence electrons. We show that under ambient conditions, the electron localizes into a cavity close to the surface of the liquid cluster. This cavity is, however, more flexible and accessible to water molecules than an analogous area around negatively charged ions. The dynamical process of electron attachment to a neutral water cluster is strongly temperature dependent. Under ambient conditions, the electron relaxes in the liquid cluster and becomes indistinguishable from an equilibrated, solvated electron on a picosecond time scale. In contrast, for solid, cryogenic systems, the electron only partially localizes outside of the cluster, being trapped in a metastable, weakly bound "cushion-like" state. Strongly bound states under cryogenic conditions could only be prepared by cooling equilibrated, liquid, negatively charged clusters. These calculations allow us to rationalize how different isomers of electrons in cryogenic clusters can be observed experimentally. Our results also bring into question the direct extrapolation of properties of cryogenic, negatively charged water clusters to those of electrons in the bulk liquid. Ab initio molecular dynamics represents a unique computational tool for investigating the reactivity of the solvated electron in water. As a prototype, the electron-proton reaction was followed in the 32-water cluster. In accord with experiment, the molecular mechanism is a proton transfer process that is not diffusion limited, but rather controlled by a proton-induced deformation of the excess electron's solvent shell. We demonstrate the necessary ingredients of a successful density functional methodology for the hydrated electron that avoids potential pitfalls, such as self-interaction error, insufficient basis set, or lack of dispersion interactions. We also benchmark the density functional theory methods and outline the path to faithful ab initio simulations of dynamics and reactivity of electrons solvated in extended aqueous systems.
Collapse
Affiliation(s)
- Ondrej Marsalek
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic and Center for Biomolecules and Complex Molecular Systems, Flemingovo nám. 2, 16610 Prague 6, Czech Republic
| | - Frank Uhlig
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic and Center for Biomolecules and Complex Molecular Systems, Flemingovo nám. 2, 16610 Prague 6, Czech Republic
| | - Joost VandeVondele
- Physical Chemistry Institute, Zürich University, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
| | - Pavel Jungwirth
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic and Center for Biomolecules and Complex Molecular Systems, Flemingovo nám. 2, 16610 Prague 6, Czech Republic
| |
Collapse
|
21
|
Pomogaev V, Pomogaeva A, Avramov P, Jalkanen KJ, Kachin S. Thermo-dynamical contours of electronic-vibrational spectra simulated using the statistical quantum–mechanical methods. Theor Chem Acc 2011. [DOI: 10.1007/s00214-011-0936-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|
22
|
Larsen RE, Glover WJ, Schwartz BJ. Response to Comments on “Does the Hydrated Electron Occupy a Cavity?”. Science 2011. [DOI: 10.1126/science.1197884] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- Ross E. Larsen
- Center for Scientific Computing, National Renewable Energy Laboratory, Golden, CO 80401–3305, USA
| | - William J. Glover
- Department of Chemistry, Stanford University, Stanford, CA 94305–5080, USA
| | - Benjamin J. Schwartz
- Department of Chemistry and Biochemistry, University of California–Los Angeles, Los Angeles, CA 90095–1569, USA
| |
Collapse
|
23
|
Herbert JM, Jacobson LD. Nature's most squishy ion: The important role of solvent polarization in the description of the hydrated electron. INT REV PHYS CHEM 2011. [DOI: 10.1080/0144235x.2010.535342] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
|
24
|
Yan Y, Lin M, Katsumura Y, Fu H, Muroya Y. Solvated electrons at elevated temperatures in different alcohols: Temperature and molecular structure effects. Radiat Phys Chem Oxf Engl 1993 2010. [DOI: 10.1016/j.radphyschem.2010.07.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
25
|
Wang XJ, Zhu Q, Li YK, Cheng XM, Li XY, Fu KX, He FC. Vertical Detachment Energy of Hydrated Electron Based on a Modified Form of Solvent Reorganization Energy. J Phys Chem B 2010; 114:2189-97. [DOI: 10.1021/jp908759s] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Xing-Jian Wang
- College of Chemical Engineering, Sichuan University, Chengdu, 610065, People’s Republic of China
| | - Quan Zhu
- College of Chemical Engineering, Sichuan University, Chengdu, 610065, People’s Republic of China
| | - Yun-Kui Li
- College of Chemical Engineering, Sichuan University, Chengdu, 610065, People’s Republic of China
| | - Xue-Min Cheng
- College of Chemical Engineering, Sichuan University, Chengdu, 610065, People’s Republic of China
| | - Xiang-Yuan Li
- College of Chemical Engineering, Sichuan University, Chengdu, 610065, People’s Republic of China
| | - Ke-Xiang Fu
- College of Chemical Engineering, Sichuan University, Chengdu, 610065, People’s Republic of China
| | - Fu-Cheng He
- College of Chemical Engineering, Sichuan University, Chengdu, 610065, People’s Republic of China
| |
Collapse
|
26
|
Hare PM, Price EA, Stanisky CM, Janik I, Bartels DM. Solvated Electron Extinction Coefficient and Oscillator Strength in High Temperature Water. J Phys Chem A 2010; 114:1766-75. [DOI: 10.1021/jp909789b] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Patrick M. Hare
- Radiation Laboratory, University of Notre Dame, Notre Dame, Indiana 46556
| | - Erica A. Price
- Radiation Laboratory, University of Notre Dame, Notre Dame, Indiana 46556
| | | | - Ireneusz Janik
- Radiation Laboratory, University of Notre Dame, Notre Dame, Indiana 46556
| | - David M. Bartels
- Radiation Laboratory, University of Notre Dame, Notre Dame, Indiana 46556
| |
Collapse
|
27
|
Kratz S, Torres-Alacan J, Urbanek J, Lindner J, Vöhringer P. Geminate recombination of hydrated electrons in liquid-to-supercritical water studied by ultrafast time-resolved spectroscopy. Phys Chem Chem Phys 2010; 12:12169-76. [DOI: 10.1039/c0cp00762e] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
28
|
Tay KA, Boutin A. Hydrated Electron Diffusion: The Importance of Hydrogen-Bond Dynamics. J Phys Chem B 2009; 113:11943-9. [DOI: 10.1021/jp810538f] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- Kafui A. Tay
- Laboratoire de Chimie Physique, Université de Paris-Sud XI, 91405 Orsay Cedex, France
| | - Anne Boutin
- Laboratoire de Chimie Physique, Université de Paris-Sud XI, 91405 Orsay Cedex, France
| |
Collapse
|
29
|
Madarász A, Rossky PJ, Turi L. Interior- and surface-bound excess electron states in large water cluster anions. J Chem Phys 2009; 130:124319. [PMID: 19334842 DOI: 10.1063/1.3094732] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We present the results of mixed quantum/classical simulations on relaxed thermal nanoscale water cluster anions, (H(2)O)(n)(-), with n=200, 500, 1000, and 8000. By using initial equilibration with constraints, we investigate stable/metastable negatively charged water clusters with both surface-bound and interior-bound excess electron states. Characterization of these states is performed in terms of geometrical parameters, energetics, and optical absorption spectroscopy of the clusters. The calculations provide data characterizing these states in the gap between previously published calculations and experiments on smaller clusters and the limiting cases of either an excess electron in bulk water or an excess electron at an infinite water/air interface. The present results are in general agreement with previous simulations and provide a consistent picture of the evolution of the physical properties of water cluster anions with size over the entire size range, including results for vertical detachment energies and absorption spectra that would signify their presence. In particular, the difference in size dependence between surface-bound and interior-bound state absorption spectra is dramatic, while for detachment energies the dependence is qualitatively the same.
Collapse
Affiliation(s)
- Adám Madarász
- Department of Physical Chemistry, Eötvös Loránd University, Budapest 112, P. O. Box 32, Budapest H-1518, Hungary.
| | | | | |
Collapse
|
30
|
Jacobson LD, Williams CF, Herbert JM. The static-exchange electron-water pseudopotential, in conjunction with a polarizable water model: A new Hamiltonian for hydrated-electron simulations. J Chem Phys 2009; 130:124115. [DOI: 10.1063/1.3089425] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
|
31
|
Pomogaev V, Pomogaeva A, Aoki Y. Absorption Spectra of Estradiol and Tryptophan Constructed by the Statistical and Elongation Methods. J Phys Chem A 2009; 113:1429-33. [DOI: 10.1021/jp808262h] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Vladimir Pomogaev
- Department of Molecular and Material Sciences, Faculty of Engineering Sciences, Kyushu University, 6-1 Kasuga-Park, Fukuoka, 816-8580, Japan, Interdisciplinary Graduate School of Engineering Science, Kyushu University, 6-1 Kasuga-Park, Fukuoka, 816-8580, Japan, and Japan Science and Technology Agency, CREST, 4-1-8 Hon-chou, Kawaguchi, Saitama 332-0012, Kyushu University, 6-1 Kasuga-Park, Fukuoka, 816-8580, Japan
| | - Anna Pomogaeva
- Department of Molecular and Material Sciences, Faculty of Engineering Sciences, Kyushu University, 6-1 Kasuga-Park, Fukuoka, 816-8580, Japan, Interdisciplinary Graduate School of Engineering Science, Kyushu University, 6-1 Kasuga-Park, Fukuoka, 816-8580, Japan, and Japan Science and Technology Agency, CREST, 4-1-8 Hon-chou, Kawaguchi, Saitama 332-0012, Kyushu University, 6-1 Kasuga-Park, Fukuoka, 816-8580, Japan
| | - Yuriko Aoki
- Department of Molecular and Material Sciences, Faculty of Engineering Sciences, Kyushu University, 6-1 Kasuga-Park, Fukuoka, 816-8580, Japan, Interdisciplinary Graduate School of Engineering Science, Kyushu University, 6-1 Kasuga-Park, Fukuoka, 816-8580, Japan, and Japan Science and Technology Agency, CREST, 4-1-8 Hon-chou, Kawaguchi, Saitama 332-0012, Kyushu University, 6-1 Kasuga-Park, Fukuoka, 816-8580, Japan
| |
Collapse
|
32
|
Sommerfeld T, DeFusco A, Jordan KD. Model Potential Approaches for Describing the Interaction of Excess Electrons with Water Clusters: Incorporation of Long-Range Correlation Effects. J Phys Chem A 2008; 112:11021-35. [DOI: 10.1021/jp806077h] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- Thomas Sommerfeld
- Department of Chemistry and Physics, Southeastern Louisiana University, Hammond, Louisiana 70402, and Department of Chemistry and Center for Molecular and Materials Simulations, University of Pittsburgh, Pittsburgh, Pennsylvania 15260
| | - Albert DeFusco
- Department of Chemistry and Physics, Southeastern Louisiana University, Hammond, Louisiana 70402, and Department of Chemistry and Center for Molecular and Materials Simulations, University of Pittsburgh, Pittsburgh, Pennsylvania 15260
| | - Kenneth D. Jordan
- Department of Chemistry and Physics, Southeastern Louisiana University, Hammond, Louisiana 70402, and Department of Chemistry and Center for Molecular and Materials Simulations, University of Pittsburgh, Pittsburgh, Pennsylvania 15260
| |
Collapse
|
33
|
Hanna G, Geva E. Computational Study of the One and Two Dimensional Infrared Spectra of a Vibrational Mode Strongly Coupled to Its Environment: Beyond the Cumulant and Condon Approximations. J Phys Chem B 2008; 112:12991-3004. [DOI: 10.1021/jp804120v] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Gabriel Hanna
- Department of Chemistry and FOCUS center, University of Michigan, Ann Arbor, Michigan 48109-1055
| | - Eitan Geva
- Department of Chemistry and FOCUS center, University of Michigan, Ann Arbor, Michigan 48109-1055
| |
Collapse
|
34
|
Tay KA, Coudert FX, Boutin A. Mechanism and kinetics of hydrated electron diffusion. J Chem Phys 2008; 129:054505. [DOI: 10.1063/1.2964101] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
|
35
|
Hanna G, Geva E. Vibrational Energy Relaxation of a Hydrogen-Bonded Complex Dissolved in a Polar Liquid via the Mixed Quantum−Classical Liouville Method. J Phys Chem B 2008; 112:4048-58. [DOI: 10.1021/jp076155b] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Gabriel Hanna
- Department of Chemistry and FOCUS center, University of Michigan, Ann Arbor, Michigan 48109-1055
| | - Eitan Geva
- Department of Chemistry and FOCUS center, University of Michigan, Ann Arbor, Michigan 48109-1055
| |
Collapse
|
36
|
Coe JV, Williams SM, Bowen KH. Photoelectron spectra of hydrated electron clustersvs.cluster size: connecting to bulk. INT REV PHYS CHEM 2008. [DOI: 10.1080/01442350701783543] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
|
37
|
Lindner J, Unterreiner AN, Vöhringer P. Femtosecond relaxation dynamics of solvated electrons in liquid ammonia. Chemphyschem 2007; 7:363-9. [PMID: 16463329 DOI: 10.1002/cphc.200500467] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The ultrafast relaxation dynamics of the well-known solvated electron in liquid ammonia solutions are investigated with femtosecond near-infrared pump-probe absorption spectroscopy. Immediately after photoexcitation, the dynamic absorption spectrum of the electron is substantially red-shifted with respect to its stationary spectrum. A subsequent dynamic blue shift of the pump-probe spectrum occurs on a timescale of 150 fs. The data are understood in terms of ground-state "cooling" and can be quantitatively simulated by an intuitive temperature-jump model employing a dynamically evolving Kubo line shape for the electronic resonance. A simple estimate implies that, on average, the electron in the liquid is coordinated to six nearest-neighbor ammonia molecules. An equivalent analysis of the data based on a bubble-formation/cavity-contraction mechanism is briefly outlined.
Collapse
Affiliation(s)
- Jörg Lindner
- Institut für Physikalische und Theoretische Chemie, Rheinische Friedrich-Wilhelms-Universität Bonn, Wegelerstrasse 12, 53115 Bonn (Germany)
| | | | | |
Collapse
|
38
|
Madarász A, Rossky PJ, Turi L. Excess electron relaxation dynamics at water/air interfaces. J Chem Phys 2007; 126:234707. [PMID: 17600435 DOI: 10.1063/1.2741514] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We have performed mixed quantum-classical molecular dynamics simulations of the relaxation of a ground state excess electron at interfaces of different phases of water with air. The investigated systems included ambient water/air, supercooled water/air, Ih ice/air, and amorphous solid water/air interfaces. The present work explores the possible connections of the examined interfacial systems to finite size cluster anions and the three-dimensional infinite, fully hydrated electron. Localization site analyses indicate that in the absence of nuclear relaxation the electron localizes in a shallow potential trap on the interface in all examined systems in a diffuse, surface-bound (SB) state. With relaxation, the weakly bound electron undergoes an ultrafast localization and stabilization on the surface with the concomitant collapse of its radius. In the case of the ambient liquid interface the electron slowly (on the 10 ps time scale) diffuses into the bulk to form an interior-bound state. In each other case, the excess electron persists on the interface in SB states. The relaxation dynamics occur through distinct SB structures which are easily distinguishable by their energetics, geometries, and interactions with the surrounding water bath. The systems exhibiting the most stable SB excess electron states (supercooled water/air and Ih ice/air interfaces) are identified by their characteristic hydrogen-bonding motifs which are found to contain double acceptor-type water molecules in the close vicinity of the electron. These surface states correlate reasonably with those extrapolated to infinite size from simulated water cluster anions.
Collapse
Affiliation(s)
- Adám Madarász
- Department of Physical Chemistry, Eötvös Loránd University, Budapest 112, P.O. Box 32, Budapest H-1518, Hungary
| | | | | |
Collapse
|
39
|
Lin M, Kumagai Y, Lampre I, Coudert FX, Muroya Y, Boutin A, Mostafavi M, Katsumura Y. Temperature effect on the absorption spectrum of the hydrated electron paired with a lithium cation in deuterated water. J Phys Chem A 2007; 111:3548-53. [PMID: 17429955 DOI: 10.1021/jp070615j] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The absorption spectra of the hydrated electron in 1.0 to 4.0 M LiCl or LiClO4 deuterated water solutions were measured by pulse radiolysis techniques from room temperature to 300 degrees C at a constant pressure of 25 MPa. The results show that when the temperature is increased and the density is decreased, the absorption spectrum of the electron in the presence of a lithium cation is shifted to lower energies. Quantum classical molecular dynamics (QCMD) simulations of an excess electron in bulk water and in the presence of a lithium cation have been performed to compare with the experimental results. According to the QCMD simulations, the change in the shape of the spectrum is due to one of the three p-like excited states of the solvated electron destabilized by core repulsion. The study of s --> p transition energies for the three p-excited states reveals that for temperatures higher than room temperature, there is a broadening of each individual s --> p absorption band due to a less structured water solvation shell.
Collapse
Affiliation(s)
- Mingzhang Lin
- Department of Nuclear Engineering and Management, School of Engineering, The University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-8656, Japan
| | | | | | | | | | | | | | | |
Collapse
|
40
|
|
41
|
Ghandi K, Clark IP, Lord JS, Cottrell SP. Laser-muon spin spectroscopy in liquids—A technique to study the excited state chemistry of transients. Phys Chem Chem Phys 2007; 9:353-9. [PMID: 17199151 DOI: 10.1039/b615184c] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This study introduces laser-muon spin spectroscopy in the liquid phase, which extends muonium chemistry in liquids to the realm of excited states and enables the detection of muoniated molecules by their spin evolution after laser excitation. This leads to new opportunities to study the Kinetic Isotope Effects (KIEs) of muonium/atomic hydrogen reactions and to probe transient chemistry in radiolysis processes involved in muonium formation, as well as muoniated intermediates in excited states.
Collapse
|
42
|
Bedard-Hearn MJ, Larsen RE, Schwartz BJ. Moving solvated electrons with light: Nonadiabatic mixed quantum/classical molecular dynamics simulations of the relocalization of photoexcited solvated electrons in tetrahydrofuran (THF). J Chem Phys 2006; 125:194509. [PMID: 17129125 DOI: 10.1063/1.2358131] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Motivated by recent ultrafast spectroscopic experiments [Martini et al., Science 293, 462 (2001)], which suggest that photoexcited solvated electrons in tetrahydrofuran (THF) can relocalize (that is, return to equilibrium in solvent cavities far from where they started), we performed a series of nonequilibrium, nonadiabatic, mixed quantum/classical molecular dynamics simulations that mimic one-photon excitation of the THF-solvated electron. We find that as photoexcited THF-solvated electrons relax to their ground states either by continuous mixing from the excited state or via nonadiabatic transitions, approximately 30% of them relocalize into cavities that can be over 1 nm away from where they originated, in close agreement with the experiments. A detailed investigation shows that the ability of excited THF-solvated electrons to undergo photoinduced relocalization stems from the existence of preexisting cavity traps that are an intrinsic part of the structure of liquid THF. This explains why solvated electrons can undergo photoinduced relocalization in solvents like THF but not in solvents like water, which lack the preexisting traps necessary to stabilize the excited electron in other places in the fluid. We also find that even when they do not ultimately relocalize, photoexcited solvated electrons in THF temporarily visit other sites in the fluid, explaining why the photoexcitation of THF-solvated electrons is so efficient at promoting recombination with nearby scavengers. Overall, our study shows that the defining characteristic of a liquid that permits the photoassisted relocalization of solvated electrons is the existence of nascent cavities that are attractive to an excess electron; we propose that other such liquids can be found from classical computer simulations or neutron diffraction experiments.
Collapse
Affiliation(s)
- Michael J Bedard-Hearn
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095-1569, USA
| | | | | |
Collapse
|
43
|
|
44
|
Spezia R, Nicolas C, Archirel P, Boutin A. Molecular dynamics simulations of the Ag+ or Na+ cation with an excess electron in bulk water. J Chem Phys 2006; 120:5261-8. [PMID: 15267397 DOI: 10.1063/1.1648631] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The properties of an excess electron interacting with a monovalent cation in bulk water are studied by molecular dynamics simulations. Sodium and silver cations are chosen as prototypical cases because of their very different redox properties. In both cases, mixed quantum classical molecular dynamics simulations reproduce the experimental UV-Vis spectra. In the case of silver, we observe a highly polarized neutral atom, corresponding to a dipolar excitonic state. For sodium a contact cation/electron pair is observed. Free energy curves along the cation electron coordinate are calculated using quantum Umbrella Sampling technique. The relative stability of the different chemical species is discussed.
Collapse
Affiliation(s)
- Riccardo Spezia
- Laboratoire de Chimie Physique, UMR 8000, CNRS, Université de Paris-Sud, 91405 Orsay Cedex, France
| | | | | | | |
Collapse
|
45
|
Turi L, Madarász A, Rossky PJ. Excess electron localization sites in neutral water clusters. J Chem Phys 2006; 125:014308. [PMID: 16863299 DOI: 10.1063/1.2213965] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
We present approximate pseudopotential quantum-mechanical calculations of the excess electron states of equilibrated neutral water clusters sampled by classical molecular dynamics simulations. The internal energy of the clusters are representative of those present at temperatures of 200 and 300 K. Correlated electronic structure calculations are used to validate the pseudopotential for this purpose. We find that the neutral clusters support localized, bound excess electron ground states in about 50% of the configurations for the smallest cluster size studied (n = 20), and in almost all configurations for larger clusters (n > 66). The state is always exterior to the molecular frame, forming typically a diffuse surface state. Both cluster size and temperature dependence of energetic and structural properties of the clusters and the electron distribution are explored. We show that the stabilization of the electron is strongly correlated with the preexisting instantaneous dipole moment of the neutral clusters, and its ground state energy is reflected in the electronic radius. The findings are consistent with electron attachment via an initial surface state. The hypothetical spectral dynamics following such attachment is also discussed.
Collapse
Affiliation(s)
- László Turi
- Department of Physical Chemistry, Eötvös Loránd University, P.O. Box 32, H-1518 Budapest 112, Hungary.
| | | | | |
Collapse
|
46
|
Coe JV, Arnold ST, Eaton JG, Lee GH, Bowen KH. Photoelectron spectra of hydrated electron clusters: Fitting line shapes and grouping isomers. J Chem Phys 2006; 125:014315. [PMID: 16863306 DOI: 10.1063/1.2212415] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
The photoelectron spectra of (H2O)(n = 2-69) - and (D2O)(n = 2-23) - are presented, and their spectral line shapes are analyzed in detail. This analysis revealed the presence of three different groupings of species, each of which are seen over the range, n = 11-16. These three groups are designated as dipole boundlike states, seen from n = 2-16, intermediate states, found from n = 6-16, and bulk embryonts, starting at n = 11 and continuing up through the largest sizes studied. Almost two decades ago [J. V. Coe et al., J. Chem. Phys. 92, 3980 (1990)], before the present comprehensive analysis, we concluded that the latter category of species were embryonic hydrated electrons with internalizing excess electrons (thus the term embryonts). Recent experiments with colder expansion (high stagnation chamber pressures) conditions by Neumark and coworkers [J. R. R. Verlet et al., Science 307, 93 (2005)] have also found three groups of isomers including the long-sought-after surface states of large water cluster anions. This work confirms that the species here designated as embryonts are in the process of internalizing the excess electron states as the cluster size increases (for n > or = 11).
Collapse
Affiliation(s)
- James V Coe
- Department of Chemistry, The Ohio State University, Columbus, Ohio 43210, USA.
| | | | | | | | | |
Collapse
|
47
|
Coudert FX, Archirel P, Boutin A. Molecular Dynamics Simulations of Electron−Alkali Cation Pairs in Bulk Water. J Phys Chem B 2005; 110:607-15. [PMID: 16471573 DOI: 10.1021/jp0542975] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The structural, dynamic, and thermodynamic properties of an excess electron interacting with an alkali cation (Na+, K+, Li+) in bulk water were investigated by means of a mixed quantum-classical molecular dynamics simulation technique. This study includes a reparametrization of the electron-cation pseudopotentials. The free energy calculations for all three systems show that a contact electron-cation pair can be observed, which is either as stable as the dissociated pair (Li+) or more stable by only a few kT (Na+, K+). Given that the dissociation barrier is also quite small, we suggest that the average cation-electron distance in the experiments at room temperature will not depend on this free energy profile but rather on the minimization of the Coulombic repulsive interaction between like charges in the solvent medium. This enables us to compare the present molecular dynamics simulations with the spectroscopic data obtained for different ionic strengths. The overall trend of the UV-vis hydrated absorption spectra, namely, the shift toward shorter wavelengths at high ionic strengths, is fairly well reproduced. This confirms our hypothesis of statistical distribution of the cations and solvated electrons.
Collapse
Affiliation(s)
- François-Xavier Coudert
- Laboratoire de Chimie Physique UMR 8000, CNRS, Université de Paris-Sud 11, 91405 Orsay Cedex, France
| | | | | |
Collapse
|
48
|
Bonin J, Lampre I, Mostafavi M. Absorption spectrum of the hydrated electron paired with nonreactive metal cations. Radiat Phys Chem Oxf Engl 1993 2005. [DOI: 10.1016/j.radphyschem.2005.03.016] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
49
|
Turi L, Sheu WS, Rossky PJ. Characterization of excess electrons in water-cluster anions by quantum simulations. Science 2005; 309:914-7. [PMID: 16081731 DOI: 10.1126/science.1115808] [Citation(s) in RCA: 182] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Water-cluster anions can serve as a bridge to understand the transition from gaseous species to the bulk hydrated electron. However, debate continues regarding how the excess electron is bound in (H2O)-n, as an interior, bulklike, or surface electronic state. To address the uncertainty, the properties of (H2O)-n clusters with 20 to 200 water molecules have been evaluated by mixed quantum-classical simulations. The theory reproduces every observed energetic, spectral, and structural trend with cluster size that is seen in experimental photoelectron and optical absorption spectra. More important, surface states and interior states each manifest a characteristic signature in the simulation data. The results strongly support assignment of surface-bound electronic states to the water-cluster anions in published experimental studies thus far.
Collapse
Affiliation(s)
- László Turi
- Eötvös Loránd University, Department of Physical Chemistry, Budapest 112, Post Office Box 32, H-1518, Hungary
| | | | | |
Collapse
|
50
|
Boutin A, Spezia R, Coudert FX, Mostafavi M. Molecular dynamics simulations of the temperature and density dependence of the absorption spectra of hydrated electron and solvated silver atom in water. Chem Phys Lett 2005. [DOI: 10.1016/j.cplett.2005.05.012] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|