1
|
Jordan CJC, Coons MP, Herbert JM, Verlet JRR. Spectroscopy and dynamics of the hydrated electron at the water/air interface. Nat Commun 2024; 15:182. [PMID: 38167300 PMCID: PMC10762076 DOI: 10.1038/s41467-023-44441-2] [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: 07/31/2023] [Accepted: 12/13/2023] [Indexed: 01/05/2024] Open
Abstract
The hydrated electron, e-(aq), has attracted much attention as a central species in radiation chemistry. However, much less is known about e-(aq) at the water/air surface, despite its fundamental role in electron transfer processes at interfaces. Using time-resolved electronic sum-frequency generation spectroscopy, the electronic spectrum of e-(aq) at the water/air interface and its dynamics are measured here, following photo-oxidation of the phenoxide anion. The spectral maximum agrees with that for bulk e-(aq) and shows that the orbital density resides predominantly within the aqueous phase, in agreement with supporting calculations. In contrast, the chemistry of the interfacial hydrated electron differs from that in bulk water, with e-(aq) diffusing into the bulk and leaving the phenoxyl radical at the surface. Our work resolves long-standing questions about e-(aq) at the water/air interface and highlights its potential role in chemistry at the ubiquitous aqueous interface.
Collapse
Affiliation(s)
| | - Marc P Coons
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH, USA
| | - John M Herbert
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH, USA.
| | - Jan R R Verlet
- Department of Chemistry, Durham University, Durham, DH1 4LJ, UK.
| |
Collapse
|
2
|
Yamamoto YI, Suzuki T. Ultrafast Geminate Recombination Facilitated by Hydrogen-Atom Transfer in Charge Transfer Reactions from Hydroxide and Methoxide Ions. J Phys Chem Lett 2023; 14:10463-10468. [PMID: 37963188 DOI: 10.1021/acs.jpclett.3c02815] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2023]
Abstract
Previous transient absorption spectroscopy (TAS) hinted at an exceptionally rapid geminate recombination process in charge transfer reactions involving OH- or OD- ions in liquid water and CH3O- ions in liquid methanol. However, a comprehensive investigation of these dynamics using TAS has been hindered by the technical challenges stemming from the ultrafast spectral shift that spans a wide wavelength range from the mid-infrared to the visible on the subpicosecond time scale. To address these challenges, we have employed ultraviolet time-resolved photoelectron spectroscopy of aqueous solutions, enabling us to observe and analyze the complete dynamics, including electron detachment, solvation, and geminate recombination. Our findings are consistent with those of Iglev et al. ( J. Phys. Chem. Lett. 2015, 6, 986-992), supporting the hypothesis that the structural diffusion of OH/OD/CH3O induced by a presolvated electron plays a pivotal role in facilitating ultrafast geminate recombination.
Collapse
Affiliation(s)
- Yo-Ichi Yamamoto
- Department of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwakecho, Sakyo-Ku, Kyoto 606-8502, Japan
| | - Toshinori Suzuki
- Department of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwakecho, Sakyo-Ku, Kyoto 606-8502, Japan
| |
Collapse
|
3
|
Li K, Chen Z, Jin X, Tian H, Song Z, Zhang Q, Xu D, Hong R. Theoretical investigation of Aryl/Alkyl halide reduction with hydrated electrons from energy and AIMD aspects. J Mol Model 2023; 29:142. [PMID: 37061582 DOI: 10.1007/s00894-023-05553-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Accepted: 04/10/2023] [Indexed: 04/17/2023]
Abstract
CONTEXT In this study, the reactions of hydrated electron (e-(aq)) with alkyl and aryl halides were simulated with an ab initial molecular dynamics (AIMD) method to reveal the underlying mechanism. An original protocol was developed for preparing the proper initial wavefunction guess of AIMD, in which a single electron was curled in a tetrahedral cavity of four water molecules. Our results show that the stability of e-(aq) increases with the hydrogen bond grid integrity. The organic halides prefer to react with e-(aq) in neutral or alkaline environment, while they are more likely to react with hydrogen radical (the product of e-(aq) and proton) under acidic conditions. The reaction between fluorobenzene/fluoromethane and hydrogen radical is considered as the least favorable reaction due to the highest reaction barriers. The bond dissociation energy (BDE) suggested that the cleavage of the carbon-halogen bond of their anion radical might be a thermodynamically favorable reaction. AIMD results indicated that the LUMO or higher orbitals were the e-(aq) migration destination. The transplanted electron enhanced carbon-halogen bond vibration intensively, leading to bond cleavage. The solvation process of the departing halogen anions was observed in both fluorobenzene and fluoromethane AIMD simulation, indicating that it might have a significant effect on enthalpy. Side reactions and byproducts obtained during the AIMD simulation suggested the complexity of the e-(aq) reactions and further investigation was needed to fully understand the reaction mechanisms. This study provided theoretical insight into the pollutant environmental fate and constructed a methodological foundation for AIMD simulation of analogous free radical reactions. METHODS The theoretical calculation was conducted on the combination of Gaussian16 and ORCA5.0.3 software packages. The initial geometries, as well as the wavefunction initial guesses, were obtained at PBE0/ma-def2-TZVP/IEFPCM-water level in Gaussian16 unless otherwise stated. AIMD simulations were performed at the same level in ORCA. Wavefunction analysis was carried out with Multiwfn. The details methods were described in the section "Computational details" section.
Collapse
Affiliation(s)
- Kaixin Li
- School of Chemical and Environmental Engineering, Anhui Polytechnic University, Wuhu, 241000, Anhui Province, People's Republic of China
| | - Zhanghao Chen
- School of the Environment, Nanjing University, Nanjing, 210093, People's Republic of China
- State Key Laboratory of Pollution Control and Resource Reuse, Nanjing University, Nanjing, 210093, People's Republic of China
| | - Xin Jin
- School of the Environment, Nanjing University, Nanjing, 210093, People's Republic of China
- State Key Laboratory of Pollution Control and Resource Reuse, Nanjing University, Nanjing, 210093, People's Republic of China
| | - Haoting Tian
- School of Environmental science and Engineering, Suzhou University of Science and Technology, Suzhou, 215009, China
| | - Zhenxia Song
- School of Chemical and Environmental Engineering, Anhui Polytechnic University, Wuhu, 241000, Anhui Province, People's Republic of China
| | - Qingyun Zhang
- School of Chemical and Environmental Engineering, Anhui Polytechnic University, Wuhu, 241000, Anhui Province, People's Republic of China
| | - Dayong Xu
- School of Chemical and Environmental Engineering, Anhui Polytechnic University, Wuhu, 241000, Anhui Province, People's Republic of China
| | - Ran Hong
- School of Chemical and Environmental Engineering, Anhui Polytechnic University, Wuhu, 241000, Anhui Province, People's Republic of China.
- State Key Laboratory of Pollution Control and Resource Reuse, Nanjing University, Nanjing, 210093, People's Republic of China.
| |
Collapse
|
4
|
Yamamoto YI, Suzuki T. Distortion Correction of Low-Energy Photoelectron Spectra of Liquids Using Spectroscopic Data for Solvated Electrons. J Phys Chem A 2023; 127:2440-2452. [PMID: 36917090 DOI: 10.1021/acs.jpca.2c08046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/16/2023]
Abstract
Time-resolved photoelectron spectroscopy (TRPES) enables real-time observation of ultrafast electronic dynamics in solutions. When extreme ultraviolet (EUV) probe pulses are employed, they can ionize solutes from all electronic states involved in the dynamics. However, EUV pulses also produce a strong ionization signal from a solvent that is typically 6 orders of magnitude greater than the pump-probe photoelectron signal of solutes. Alternatively, UV probe pulses enable highly sensitive and selective observation of photoexcited solutes because typical solvents such as water are transparent to UV radiation. An obstacle in such UV-TRPES measurements is spectral distortion caused by electron scattering and a yet to be identified mechanism in liquids. We have previously proposed the spectral retrieval (SR) method as an a posteriori approach to removing the distortion and overcoming this difficulty in UV-TRPES; however, its accuracy has not yet been verified by comparison with EUV-TRPES results. In the present study, we perform EUV-TRPES for charge transfer reactions in water, methanol, and ethanol, and verify SR analysis of UV-TRPES. We also estimate a previously undetermined energy-dependent intensity factor and expand the basis sets for SR analysis. The refined SR method is employed for reanalyzing the UV-TRPES data for the formation and relaxation dynamics of solvated electrons in various systems. The electron binding energy distributions for solvated electrons in liquid water, methanol, and ethanol are confirmed to be Gaussian centered at 3.78, 3.39, and 3.25 eV, respectively, in agreement with Nishitani et al. [ Sci. Adv. 2019, 5(8), eaaw6896]. An effective energy gap between the conduction band and the vacuum level at the gas-liquid interface is estimated to be 0.2 eV for liquid water and 0.1 eV for methanol and ethanol.
Collapse
Affiliation(s)
- Yo-Ichi Yamamoto
- Department of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwakecho, Sakyo-Ku, Kyoto 606-8502, Japan
| | - Toshinori Suzuki
- Department of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwakecho, Sakyo-Ku, Kyoto 606-8502, Japan
| |
Collapse
|
5
|
Yamamoto YI, Suzuki YI, Suzuki T. Charge Transfer Reactions from I - to Polar Protic Solvents Studied Using Ultrafast Extreme Ultraviolet Photoelectron Spectroscopy. J Phys Chem Lett 2023; 14:1052-1058. [PMID: 36693229 DOI: 10.1021/acs.jpclett.2c03849] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Charge transfer reactions from I- to solvent water, methanol, and ethanol were studied using extreme ultraviolet time-resolved photoelectron spectroscopy (EUV-TRPES). This technique eliminates spectral broadening, previously seen in UV-TRPES, caused by electron inelastic scattering in liquids, and enables clear observation of the temporal evolution of the spectral shape. The peak position, width, and intensity of the electron binding energy distribution indicate electron detachment and subsequent solvation and thermalization processes. Geminate recombination between detached electrons and iodine atoms is discussed using a diffusion equation and a global fitting analysis based on a kinetics model.
Collapse
Affiliation(s)
- Yo-Ichi Yamamoto
- Department of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwakecho, Sakyo-Ku, Kyoto606-8502, Japan
| | - Yoshi-Ichi Suzuki
- School of Medical Technology, Health Sciences University of Hokkaido, 1757 Kanazawa, Tobetsucho, Ishikari, Hokkaido061-0293, Japan
| | - Toshinori Suzuki
- Department of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwakecho, Sakyo-Ku, Kyoto606-8502, Japan
| |
Collapse
|
6
|
Abstract
Knowledge of the electronic structure of an aqueous solution is a prerequisite to understanding its chemical and biological reactivity and its response to light. One of the most direct ways of determining electronic structure is to use photoelectron spectroscopy to measure electron binding energies. Initially, photoelectron spectroscopy was restricted to the gas or solid phases due to the requirement for high vacuum to minimize inelastic scattering of the emitted electrons. The introduction of liquid-jets and their combination with intense X-ray sources at synchrotrons in the late 1990s expanded the scope of photoelectron spectroscopy to include liquids. Liquid-jet photoelectron spectroscopy is now an active research field involving a growing number of research groups. A limitation of X-ray photoelectron spectroscopy of aqueous solutions is the requirement to use solutes with reasonably high concentrations in order to obtain photoelectron spectra with adequate signal-to-noise after subtracting the spectrum of water. This has excluded most studies of organic molecules, which tend to be only weakly soluble. A solution to this problem is to use resonance-enhanced photoelectron spectroscopy with ultraviolet (UV) light pulses (hν ≲ 6 eV). However, the development of UV liquid-jet photoelectron spectroscopy has been hampered by a lack of quantitative understanding of inelastic scattering of low kinetic energy electrons (≲5 eV) and the impact on spectral lineshapes and positions.In this Account, we describe the key steps involved in the measurement of UV photoelectron spectra of aqueous solutions: photoionization/detachment, electron transport of low kinetic energy electrons through the conduction band, transmission through the water-vacuum interface, and transport through the spectrometer. We also explain the steps we take to record accurate UV photoelectron spectra of liquids with excellent signal-to-noise. We then describe how we have combined Monte Carlo simulations of electron scattering and spectral inversion with molecular dynamics simulations of depth profiles of organic solutes in aqueous solution to develop an efficient and widely applicable method for retrieving true UV photoelectron spectra of aqueous solutions. The huge potential of our experimental and spectral retrieval methods is illustrated using three examples. The first is a measurement of the vertical detachment energy of the green fluorescent protein chromophore, a sparingly soluble organic anion whose electronic structure underpins its fluorescence and photooxidation properties. The second is a measurement of the vertical ionization energy of liquid water, which has been the subject of discussion since the first X-ray photoelectron spectroscopy measurement in 1997. The third is a UV photoelectron spectroscopy study of the vertical ionization energy of aqueous phenol which demonstrates the possibility of retrieving true photoelectron spectra from measurements with contributions from components with different concentration profiles.
Collapse
|
7
|
Low PJ, Chu W, Nie Z, Bin Mohd Yusof MS, Prezhdo OV, Loh ZH. Observation of a transient intermediate in the ultrafast relaxation dynamics of the excess electron in strong-field-ionized liquid water. Nat Commun 2022; 13:7300. [DOI: 10.1038/s41467-022-34981-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Accepted: 11/11/2022] [Indexed: 11/28/2022] Open
Abstract
AbstractA unified picture of the electronic relaxation dynamics of ionized liquid water has remained elusive despite decades of study. Here, we employ sub-two-cycle visible to short-wave infrared pump-probe spectroscopy and ab initio nonadiabatic molecular dynamics simulations to reveal that the excess electron injected into the conduction band (CB) of ionized liquid water undergoes sequential relaxation to the hydrated electron s ground state via an intermediate state, identified as the elusive p excited state. The measured CB and p-electron lifetimes are 0.26 ± 0.02 ps and 62 ± 10 fs, respectively. Ab initio quantum dynamics yield similar lifetimes and furthermore reveal vibrational modes that participate in the different stages of electronic relaxation, with initial relaxation within the dense CB manifold coupled to hindered translational motions whereas subsequent p-to-s relaxation facilitated by librational and even intramolecular bending modes of water. Finally, energetic considerations suggest that a hitherto unobserved trap state resides ~0.3-eV below the CB edge of liquid water. Our results provide a detailed atomistic picture of the electronic relaxation dynamics of ionized liquid water with unprecedented time resolution.
Collapse
|
8
|
Scholz M, Fortune WG, Tau O, Fielding HH. Accurate Vertical Ionization Energy of Water and Retrieval of True Ultraviolet Photoelectron Spectra of Aqueous Solutions. J Phys Chem Lett 2022; 13:6889-6895. [PMID: 35862937 PMCID: PMC9358712 DOI: 10.1021/acs.jpclett.2c01768] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Accepted: 07/14/2022] [Indexed: 05/23/2023]
Abstract
Ultraviolet (UV) photoelectron spectroscopy provides a direct way of measuring valence electronic structure; however, its application to aqueous solutions has been hampered by a lack of quantitative understanding of how inelastic scattering of low-energy (<5 eV) electrons in liquid water distorts the measured electron kinetic energy distributions. Here, we present an efficient and widely applicable method for retrieving true UV photoelectron spectra of aqueous solutions. Our method combines Monte Carlo simulations of electron scattering and spectral inversion, with molecular dynamics simulations of depth profiles of organic solutes in aqueous solution. Its application is demonstrated for both liquid water, and aqueous solutions of phenol and phenolate, which are ubiquitous biologically relevant structural motifs.
Collapse
|
9
|
Signorell R, Winter B. Photoionization of the aqueous phase: clusters, droplets and liquid jets. Phys Chem Chem Phys 2022; 24:13438-13460. [PMID: 35510623 PMCID: PMC9176186 DOI: 10.1039/d2cp00164k] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
This perspective article reviews specific challenges associated with photoemission spectroscopy of bulk liquid water, aqueous solutions, water droplets and water clusters. The main focus lies on retrieving accurate energetics and photoelectron angular information from measured photoemission spectra, and on the question how these quantities differ in different aqueous environments. Measured photoelectron band shapes, vertical binding energies (ionization energies), and photoelectron angular distributions are influenced by various phenomena. We discuss the influences of multiple energy-dependent electron scattering in aqueous environments, and we discuss different energy referencing methods, including the application of a bias voltage to access absolute energetics of solvent and solute. Recommendations how to account for or minimize the influence of electron scattering are provided. The example of the hydrated electron in different aqueous environments illustrates how one can account for electron scattering, while reliable methods addressing parasitic potentials and proper energy referencing are demonstrated for ionization from the outermost valence orbital of neat liquid water. This perspective article reviews specific challenges associated with photoemission spectroscopy of bulk liquid water, aqueous solutions, water droplets and water clusters.![]()
Collapse
Affiliation(s)
- Ruth Signorell
- Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 2, 8093 Zürich, Switzerland.
| | - Bernd Winter
- Molecular Physics Department, Fritz-Haber-Institute der Max-Planck-Gesellschaft, Faradayweg 4-6, 14196 Berlin, Germany.
| |
Collapse
|
10
|
Ban L, Tang H, Yoder BL, Signorell R. Time-dependent photoemission from droplets: influence of size and charge on the photophysics near the surface. Faraday Discuss 2022; 236:461-484. [PMID: 35507329 PMCID: PMC9408814 DOI: 10.1039/d1fd00108f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Photoemission from submicrometer droplets containing a mixture of dioctyl phthalate and dioctyl sebacate was investigated by femtosecond and nanosecond photoionization. Photoelectron spectra recorded after ionization with single 4.7 eV femtosecond or nanosecond laser pulses showed marked differences between the two cases. These differences were attributed to ionization of long-lived states which only occurred within the duration of the nanosecond pulse. The tentative assignment of the long-lived states to dioctyl phthalate triplet states is discussed. A nanosecond–femtosecond pump–probe scheme using 4.7 eV (pump) and 3.1 eV (probe) pulses was used to investigate the decay dynamics of these long-lived states. The dynamics showed an accelerated decay rate at higher dioctyl phthalate concentrations. Furthermore, the dependence of the decay dynamics on droplet size and charge was investigated. The decay of the long-lived states was found to be faster in smaller droplets as well as in neutral droplets compared with both positively and negatively charged droplets. Possible mechanisms to explain these observations and the dominance of contributions from the droplets surface are discussed. Time-resolved photoemission spectroscopy is used to study the photophysics of droplets containing dioctyl phthalate. Long-lived excited states survive longer at lower phthalate concentrations, and in larger or electrically charged droplets.![]()
Collapse
Affiliation(s)
- Loren Ban
- Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog Weg 2, CH-8093 Zürich, Switzerland.
| | - Hanchao Tang
- Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog Weg 2, CH-8093 Zürich, Switzerland.
| | - Bruce L Yoder
- Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog Weg 2, CH-8093 Zürich, Switzerland.
| | - Ruth Signorell
- Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog Weg 2, CH-8093 Zürich, Switzerland.
| |
Collapse
|
11
|
Majer K, Ma L, von Issendorff B. Photoelectron Spectroscopy of Large Water Cluster Anions. J Phys Chem A 2021; 125:8426-8433. [PMID: 34533952 DOI: 10.1021/acs.jpca.1c06761] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Photoelectron spectra of large size selected water cluster anions (H2O)n- (n = 100-1100) have been measured at a low cluster temperature (80 K). An extensive peak analysis has been conducted in order to determine average and isomer-resolved vertical detachment energies (VDE) of the hydrated electron. This allows us, in combination with the reevaluated data of the previously reported results on small- and medium-sized water cluster anions ( J. Chem. Phys. 2009, 131, 144303), to draw a comprehensive picture of the size-dependent development of the VDEs of water clusters. This allows for an improved extrapolation of the cluster VDEs to the bulk, which yields a value of 3.60 ± 0.03 eV. The general size dependence of the VDEs is in very good agreement with a standard dielectric model.
Collapse
Affiliation(s)
- Kiran Majer
- Physics Institute, University of Freiburg, Hermann-Herder-Straße 3, 79104 Freiburg, Germany.,Freiburg Material Research Center, Stefan-Meier-Straße 21, 79104 Freiburg, Germany
| | - Lei Ma
- Physics Institute, University of Freiburg, Hermann-Herder-Straße 3, 79104 Freiburg, Germany.,Tianjin International Center for Nanoparticles and Nanosystems, Tianjin University, Tianjin 300072, China
| | - Bernd von Issendorff
- Physics Institute, University of Freiburg, Hermann-Herder-Straße 3, 79104 Freiburg, Germany.,Freiburg Material Research Center, Stefan-Meier-Straße 21, 79104 Freiburg, Germany
| |
Collapse
|
12
|
Paul SK, Herbert JM. Probing Interfacial Effects on Ionization Energies: The Surprising Banality of Anion-Water Hydrogen Bonding at the Air/Water Interface. J Am Chem Soc 2021; 143:10189-10202. [PMID: 34184532 DOI: 10.1021/jacs.1c03131] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Liquid microjet photoelectron spectroscopy is an increasingly common technique to measure vertical ionization energies (VIEs) of aqueous solutes, but the interpretation of these experiments is subject to questions regarding sensitivity to bulk versus interfacial solvation environments. We have computed aqueous-phase VIEs for a set of inorganic anions, using a combination of molecular dynamics simulations and electronic structure calculations, with results that are in excellent agreement with experiment regardless of whether the simulation data are restricted to ions at the air/water interface or to those in bulk aqueous solution. Although the computed VIEs are sensitive to ion-water hydrogen bonding, we find that the short-range solvation structure is sufficiently similar in both environments that it proves impossible to discriminate between the two on the basis of the VIE, a conclusion that has important implications for the interpretation of liquid-phase photoelectron spectroscopy. More generally, analysis of the simulation data suggests that the surface activity of soft anions is largely a second or third solvation shell effect, arising from disruption of water-water hydrogen bonds and not from significant changes in first-shell anion-water hydrogen bonding.
Collapse
Affiliation(s)
- Suranjan K Paul
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States
| | - John M Herbert
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States
| |
Collapse
|
13
|
Abstract
![]()
Cluster-size-resolved
ultrafast dynamics of the solvated electron
in neutral water clusters with n = 3 to ∼200
molecules are studied with pump–probe time-of-flight mass spectrometry
after below band gap excitation. For the smallest clusters, no longer-lived
(>100–200 fs) hydrated electrons were detected, indicating
a minimum size of n ∼ 14 for being able to
sustain hydrated electrons. Larger clusters show a systematic increase
of the number of hydrated electrons per molecule on the femtosecond
to picosecond time scale. We propose that with increasing cluster
size the underlying dynamics is governed by more effective electron
formation processes combined with less effective electron loss processes,
such as ultrafast hydrogen ejection and recombination. It appears
unlikely that any size dependence of the solvent relaxation dynamics
would be reflected in the observed time-resolved ion yields.
Collapse
Affiliation(s)
- Loren Ban
- Department of Chemistry and Applied Biosciences, ETH Zurich, Vladimir-Prelog-Weg 2, CH-8093 Zurich, Switzerland
| | - Bruce L Yoder
- Department of Chemistry and Applied Biosciences, ETH Zurich, Vladimir-Prelog-Weg 2, CH-8093 Zurich, Switzerland
| | - Ruth Signorell
- Department of Chemistry and Applied Biosciences, ETH Zurich, Vladimir-Prelog-Weg 2, CH-8093 Zurich, Switzerland
| |
Collapse
|
14
|
Long J, Qiu Z, Wei J, Li D, Song X, Jin B, Zhang B. Liquid-microjet photoelectron imaging spectrometry for liquid aqueous solutions. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2021; 92:065108. [PMID: 34243573 DOI: 10.1063/5.0036471] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Accepted: 05/16/2021] [Indexed: 06/13/2023]
Abstract
A new liquid-microjet photoelectron imaging (PEI) spectrometer has been constructed that combines the liquid-microjet technique with velocity-map imaging. This novel method enables us to simultaneously measure the energy and angular distributions of the photoelectrons produced from highly volatile liquid solutions. The capability of the spectrometer has been demonstrated by recording the photoelectron image of the aqueous 2-furfural. To our knowledge, this is the first time that the PEI of liquid aqueous solutions has succeeded.
Collapse
Affiliation(s)
- Jinyou Long
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, People's Republic of China
| | - Ziheng Qiu
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, People's Republic of China
| | - Jie Wei
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, People's Republic of China
| | - Duoduo Li
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, People's Republic of China
| | - Xinli Song
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, People's Republic of China
| | - Bing Jin
- Institute of Molecular Sciences and Engineering, Institute of Frontier and Interdisciplinary Science, Shandong University, Qingdao 266235, People's Republic of China
| | - Bing Zhang
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, People's Republic of China
| |
Collapse
|
15
|
Perry C, Jordan I, Zhang P, von Conta A, Nunes FB, Wörner HJ. Photoelectron Spectroscopy of Liquid Water with Tunable Extreme-Ultraviolet Radiation: Effects of Electron Scattering. J Phys Chem Lett 2021; 12:2990-2996. [PMID: 33733779 PMCID: PMC8006141 DOI: 10.1021/acs.jpclett.0c03424] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
We report the first systematic photoelectron measurements of the three outer-valence bands of liquid water as a function of the ionizing photon energy in the near-threshold region. We use extreme-ultraviolet (XUV) radiation tunable between ∼17.1 and 35.6 eV, obtained through monochromatization of a high-harmonic source. We show that the absolute values of the apparent vertical ionization energies and their respective peak widths show a decreasing trend of their magnitudes with increasing photon energy close to the ionization threshold. We find that the observed effects do not only depend on the electron kinetic energy but are also different for the various outer-valence bands. These observations are consistent with, but not fully explained by, the effects of inelastic electron scattering.
Collapse
|
16
|
Kitajima K, Nakai Y, Sameera WMC, Tsuge M, Miyazaki A, Hidaka H, Kouchi A, Watanabe N. Delivery of Electrons by Proton-Hole Transfer in Ice at 10 K: Role of Surface OH Radicals. J Phys Chem Lett 2021; 12:704-710. [PMID: 33400539 DOI: 10.1021/acs.jpclett.0c03345] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Although water ice has been widely accepted to carry a positive charge via the transfer of excess protons through a hydrogen-bonded system, ice was recently found to be a negative charge conductor upon simultaneous exposure to electrons and ultraviolet photons at temperatures below 50 K. In this work, the mechanism of electron delivery was confirmed experimentally by both measuring currents through ice and monitoring photodissociated OH radicals on ice by using a novel method. The surface OH radicals significantly decrease upon the appearance of negative current flow, indicating that the electrons are delivered by proton-hole (OH-) transfer in ice triggered by OH- production on the surface. The mechanism of proton-hole transfer was rationalized by density functional theory calculations.
Collapse
Affiliation(s)
- Kensei Kitajima
- Institute of Low Temperature Science, Hokkaido University, Sapporo 060-0819, Japan
| | - Yoichi Nakai
- Radioactive Isotope Physics Laboratory, RIKEN Nishina Center, Saitama 351-0198, Japan
| | - W M C Sameera
- Institute of Low Temperature Science, Hokkaido University, Sapporo 060-0819, Japan
| | - Masashi Tsuge
- Institute of Low Temperature Science, Hokkaido University, Sapporo 060-0819, Japan
| | - Ayane Miyazaki
- Institute of Low Temperature Science, Hokkaido University, Sapporo 060-0819, Japan
| | - Hiroshi Hidaka
- Institute of Low Temperature Science, Hokkaido University, Sapporo 060-0819, Japan
| | - Akira Kouchi
- Institute of Low Temperature Science, Hokkaido University, Sapporo 060-0819, Japan
| | - Naoki Watanabe
- Institute of Low Temperature Science, Hokkaido University, Sapporo 060-0819, Japan
| |
Collapse
|
17
|
Ban L, West CW, Chasovskikh E, Gartmann TE, Yoder BL, Signorell R. Below Band Gap Formation of Solvated Electrons in Neutral Water Clusters? J Phys Chem A 2020; 124:7959-7965. [PMID: 32878434 PMCID: PMC7536715 DOI: 10.1021/acs.jpca.0c06935] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 09/01/2020] [Indexed: 01/25/2023]
Abstract
Below band gap formation of solvated electrons in neutral water clusters using pump-probe photoelectron imaging is compared with recent data for liquid water and with above band gap excitation studies in liquid and clusters. Similar relaxation times on the order of 200 fs and 1-2 ps are retrieved for below and above band gap excitation, in both clusters and liquid. The independence of the relaxation times from the generation process indicates that these times are dominated by the solvent response, which is significantly slower than the various solvated electron formation processes. The analysis of the temporal evolution of the vertical electron binding energy and the electron binding energy at half-maximum suggests a dependence of the solvation time on the binding energy.
Collapse
Affiliation(s)
- Loren Ban
- ETH Zurich, Department of Chemistry
and Applied Biosciences, Vladimir-Prelog-Weg 2, CH-8093 Zurich, Switzerland
| | - Christopher W. West
- ETH Zurich, Department of Chemistry
and Applied Biosciences, Vladimir-Prelog-Weg 2, CH-8093 Zurich, Switzerland
| | - Egor Chasovskikh
- ETH Zurich, Department of Chemistry
and Applied Biosciences, Vladimir-Prelog-Weg 2, CH-8093 Zurich, Switzerland
| | - Thomas E. Gartmann
- ETH Zurich, Department of Chemistry
and Applied Biosciences, Vladimir-Prelog-Weg 2, CH-8093 Zurich, Switzerland
| | - Bruce L. Yoder
- ETH Zurich, Department of Chemistry
and Applied Biosciences, Vladimir-Prelog-Weg 2, CH-8093 Zurich, Switzerland
| | - Ruth Signorell
- ETH Zurich, Department of Chemistry
and Applied Biosciences, Vladimir-Prelog-Weg 2, CH-8093 Zurich, Switzerland
| |
Collapse
|
18
|
Abstract
Intriguing properties of photoemission from free, unsupported particles and droplets were predicted nearly 50 years ago, though experiments were a technical challenge. The last few decades have seen a surge of research in the field, due to advances in aerosol technology (generation, characterization, and transfer into vacuum), the development of photoelectron imaging spectrometers, and advances in vacuum ultraviolet and ultrafast light sources. Particles and droplets offer several advantages for photoemission studies. For example, photoemission spectra are dependent on the particle's size, shape, and composition, providing a wealth of information that allows for the retrieval of genuine electronic properties of condensed phase. In this review, with a focus on submicrometer-sized, dielectric particles and droplets, we explain the utility of photoemission from such systems, summarize several applications from the literature, and present some thoughts on future research directions.
Collapse
Affiliation(s)
- Loren Ban
- Department of Chemistry and Applied Biosciences, ETH Zürich, 8093 Zürich, Switzerland;
| | - Bruce L Yoder
- Department of Chemistry and Applied Biosciences, ETH Zürich, 8093 Zürich, Switzerland;
| | - Ruth Signorell
- Department of Chemistry and Applied Biosciences, ETH Zürich, 8093 Zürich, Switzerland;
| |
Collapse
|
19
|
Bertram C, Auburger P, Bockstedte M, Stähler J, Bovensiepen U, Morgenstern K. Impact of Electron Solvation on Ice Structures at the Molecular Scale. J Phys Chem Lett 2020; 11:1310-1316. [PMID: 31985230 DOI: 10.1021/acs.jpclett.9b03723] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Electron attachment and solvation at ice structures are well-known phenomena. The energy liberated in such events is commonly understood to cause temporary changes at such ice structures, but it may also trigger permanent modifications to a yet unknown extent. We determine the impact of electron solvation on D2O structures adsorbed on Cu(111) with low-temperature scanning tunneling microscopy, two-photon photoemission, and ab initio theory. Solvated electrons, generated by ultraviolet photons, lead not only to transient but also to permanent structural changes through the rearrangement of individual molecules. The persistent changes occur near sites with a high density of dangling OD groups that facilitate electron solvation. We conclude that energy dissipation during solvation triggers permanent molecular rearrangement via vibrational excitation.
Collapse
Affiliation(s)
- Cord Bertram
- Physical Chemistry I , Ruhr-Universität Bochum , D-44780 Bochum , Germany
- Faculty of Physics , University of Duisburg-Essen , Lotharstr. 1 , D-47048 Duisburg , Germany
| | - Philipp Auburger
- Solid State Theory , Friedrich-Alexander University Erlangen-Nürnberg , Staudtstr. 7B2 , D-91058 Erlangen , Germany
| | - Michel Bockstedte
- Solid State Theory , Friedrich-Alexander University Erlangen-Nürnberg , Staudtstr. 7B2 , D-91058 Erlangen , Germany
- Chemistry and Physics of Materials , University of Salzburg , Jakob-Haringer-Str. 2a , A-5020 Salzburg , Austria
| | - Julia Stähler
- Department of Physical Chemistry , Fritz Haber Institute of the Max Planck Society , Faradayweg 4-6 , D-14195 Berlin , Germany
- Department of Physics , Freie Universität Berlin , Arnimallee 14 , D-14195 Berlin , Germany
| | - Uwe Bovensiepen
- Faculty of Physics , University of Duisburg-Essen , Lotharstr. 1 , D-47048 Duisburg , Germany
- Department of Physics , Freie Universität Berlin , Arnimallee 14 , D-14195 Berlin , Germany
| | - Karina Morgenstern
- Physical Chemistry I , Ruhr-Universität Bochum , D-44780 Bochum , Germany
| |
Collapse
|
20
|
Signorell R. Can Current Experimental Data Exclude Non-Gaussian Genuine Band Shapes in Ultraviolet Photoelectron Spectra of the Hydrated Electron? J Phys Chem Lett 2020; 11:1516-1519. [PMID: 32075380 PMCID: PMC7037147 DOI: 10.1021/acs.jpclett.0c00238] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Two recent articles present results that allegedly exclude a possible multimodal distribution of the hydrated electron in ultraviolet photoelectron spectra. The first article bases its conclusion on the assumption that the non-Gaussian genuine band shape previously retrieved for the solvated electron in liquid water is an artifact arising from insufficient electron scattering cross sections used in the retrieval. The second article excludes a multimodal band shape based on a photoelectron spectrum of the solvated electron in water clusters recorded at a single ultraviolet photon energy, and it further assumes that cluster results are transferable to the liquid without further justification. Here, we show that based on current data multimodal distributions cannot be unambiguously excluded. Furthermore, the transferability of cluster results to the liquid can be neither justified nor refuted on the basis of currently available experimental ultraviolet photoelectron spectra.
Collapse
|
21
|
Henley A, Riley J, Wang B, Fielding HH. An experimental and computational study of the effect of aqueous solution on the multiphoton ionisation photoelectron spectrum of phenol. Faraday Discuss 2020; 221:202-218. [DOI: 10.1039/c9fd00079h] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
We revisit the photoelectron spectroscopy of aqueous phenol in an effort to improve our understanding of the impact of inhomogeneous broadening and inelastic scattering on solution-phase photoelectron spectra.
Collapse
Affiliation(s)
- Alice Henley
- Department of Chemistry
- University College London
- London WC1H 0AJ
- UK
| | - Jamie W. Riley
- Department of Chemistry
- University College London
- London WC1H 0AJ
- UK
| | - Bingxing Wang
- Department of Chemistry
- University College London
- London WC1H 0AJ
- UK
| | | |
Collapse
|
22
|
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]
|
23
|
Dasgupta S, Rana B, Herbert JM. Ab Initio Investigation of the Resonance Raman Spectrum of the Hydrated Electron. J Phys Chem B 2019; 123:8074-8085. [PMID: 31442044 DOI: 10.1021/acs.jpcb.9b04895] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
According to the conventional picture, the aqueous or "hydrated" electron, e-(aq), occupies an excluded volume (cavity) in the structure of liquid water. However, simulations with certain one-electron models predict a more delocalized spin density for the unpaired electron, with no distinct cavity structure. It has been suggested that only the latter (non-cavity) structure can explain the hydrated electron's resonance Raman spectrum, although this suggestion is based on calculations using empirical frequency maps developed for neat liquid water, not for e-(aq). All-electron ab initio calculations presented here demonstrate that both cavity and non-cavity models of e-(aq) afford significant red-shifts in the O-H stretching region. This effect is nonspecific and arises due to electron penetration into frontier orbitals of the water molecules. Only the conventional cavity model, however, reproduces the splitting of the H-O-D bend (in isotopically mixed water) that is observed experimentally and arises due to the asymmetric environments of the hydroxyl moieties in the electron's first solvation shell. We conclude that the cavity model of e-(aq) is more consistent with the measured resonance Raman spectrum than is the delocalized, non-cavity model, despite previous suggestions to the contrary. Furthermore, calculations with hybrid density functionals and with Hartree-Fock theory predict that non-cavity liquid geometries afford only unbound (continuum) states for an extra electron, whereas in reality this energy level should lie more than 3 eV below vacuum level. As such, the non-cavity model of e-(aq) appears to be inconsistent with available vibrational spectroscopy, photoelectron spectroscopy, and quantum chemistry.
Collapse
Affiliation(s)
- Saswata Dasgupta
- Department of Chemistry and Biochemistry , The Ohio State University , Columbus , Ohio 43210 , United States
| | - Bhaskar Rana
- Department of Chemistry and Biochemistry , The Ohio State University , Columbus , Ohio 43210 , United States
| | - John M Herbert
- Department of Chemistry and Biochemistry , The Ohio State University , Columbus , Ohio 43210 , United States
| |
Collapse
|
24
|
Hara A, Yamamoto YI, Suzuki T. Solvated electron formation from the conduction band of liquid methanol: Transformation from a shallow to deep trap state. J Chem Phys 2019; 151:114503. [PMID: 31542023 DOI: 10.1063/1.5116818] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
We report solvated electron (esolv -) formation dynamics from the conduction band of liquid methanol studied using femtosecond time-resolved photoelectron spectroscopy. Liquid methanol is excited with vacuum UV (9.3 eV) pump pulses, and the subsequent electron dynamics are probed with UV pulses. The photoelectron signal exhibits a short-lived component (τ = 85 fs) without spectral evolution followed by a long-lived component with continuous spectral evolution over tens of picoseconds. We ascribe the former to a superexcited state, most likely the Wannier exciton, and the latter to the ground electronic state of esolv -. In order to extract accurate energetics from the observed photoelectron spectra, we employ a spectral retrieval method to account for spectral broadening and shifting due to inelastic scattering of photoelectrons in the liquid. The electron binding energy (eBE) of the initial trap state of an electron is determined to be about 1.5 eV, and its biexponential increase up to 3.4 eV is observed with time constants of 2 and 31 ps, which are greater than 0.27 and 13 ps observed for esolv - created by the charge-transfer-to-solvent reaction from CH3O- to liquid methanol. The solvation dynamics of esolv - created by the electron trapping exhibit a pseudoisosbestic point at a pump-probe delay time of around 15 ps, and the peak energy of the eBE distribution rapidly changes around that time. These results indicate that there exist two trap states, both of which exhibit increasing eBE with time; however, the eBE of the shallow trap state increases only up to 2.1 eV, and transformation to a deep trap state at 25 ps occurs to reach an eBE of 3.4 eV.
Collapse
Affiliation(s)
- Ayano Hara
- Department of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwakecho, Sakyo-Ku, Kyoto 606-8502, Japan
| | - Yo-Ichi Yamamoto
- Department of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwakecho, Sakyo-Ku, Kyoto 606-8502, Japan
| | - Toshinori Suzuki
- Department of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwakecho, Sakyo-Ku, Kyoto 606-8502, Japan
| |
Collapse
|
25
|
Affiliation(s)
- Toshinori Suzuki
- Department of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwakecho, Sakyo-Ku, Kyoto 606-8502,
Japan
| |
Collapse
|
26
|
Gartmann T, Ban L, Yoder BL, Hartweg S, Chasovskikh E, Signorell R. Relaxation Dynamics and Genuine Properties of the Solvated Electron in Neutral Water Clusters. J Phys Chem Lett 2019; 10:4777-4782. [PMID: 31382737 PMCID: PMC6734797 DOI: 10.1021/acs.jpclett.9b01802] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Accepted: 08/05/2019] [Indexed: 05/27/2023]
Abstract
We have investigated the solvation dynamics and the genuine binding energy and photoemission anisotropy of the solvated electron in neutral water clusters with a combination of time-resolved photoelectron velocity map imaging and electron scattering simulations. The dynamics was probed with a UV probe pulse following above-band-gap excitation by an EUV pump pulse. The solvation dynamics is completed within about 2 ps. Only a single band is observed in the spectra, with no indication for isomers with distinct binding energies. Data analysis with an electron scattering model reveals a genuine binding energy in the range of 3.55-3.85 eV and a genuine anisotropy parameter in the range of 0.51-0.66 for the ground-state hydrated electron. All of these observations coincide with those for liquid bulk, which is rather unexpected for an average cluster size of 300 molecules.
Collapse
|
27
|
Karashima S, Yamamoto YI, Suzuki T. Ultrafast Internal Conversion and Solvation of Electrons in Water, Methanol, and Ethanol. J Phys Chem Lett 2019; 10:4499-4504. [PMID: 31343891 DOI: 10.1021/acs.jpclett.9b01750] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Ultrafast internal conversion from the first excited state of a solvated electron in water, methanol, and ethanol is investigated using time-resolved photoelectron spectroscopy of liquid microjets and a spectral retrieval method. Photoelectron spectra corrected for inelastic scattering clearly reveal well-separated signals from the excited and ground states, and the latter enables us to analyze the solvation dynamics in the ground state after internal conversion. Measurements with 25 fs time resolution identify a rapid increase in the vertical electron binding energy of the solvated electron owing to nuclear wave packet motions in the excited state and allow us to precisely determine the internal conversion time.
Collapse
Affiliation(s)
- Shutaro Karashima
- Department of Chemistry, Graduate School of Science , Kyoto University , Kitashirakawa-Oiwakecho, Sakyo-Ku, Kyoto 606-8502 , Japan
| | - Yo-Ichi Yamamoto
- Department of Chemistry, Graduate School of Science , Kyoto University , Kitashirakawa-Oiwakecho, Sakyo-Ku, Kyoto 606-8502 , Japan
| | - Toshinori Suzuki
- Department of Chemistry, Graduate School of Science , Kyoto University , Kitashirakawa-Oiwakecho, Sakyo-Ku, Kyoto 606-8502 , Japan
| |
Collapse
|
28
|
Nishitani J, Yamamoto YI, West CW, Karashima S, Suzuki T. Binding energy of solvated electrons and retrieval of true UV photoelectron spectra of liquids. SCIENCE ADVANCES 2019; 5:eaaw6896. [PMID: 31497644 PMCID: PMC6716956 DOI: 10.1126/sciadv.aaw6896] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Accepted: 07/24/2019] [Indexed: 05/24/2023]
Abstract
The electronic energy and dynamics of solvated electrons, the simplest yet elusive chemical species, is of interest in chemistry, physics, and biology. Here, we present the electron binding energy distributions of solvated electrons in liquid water, methanol, and ethanol accurately measured using extreme ultraviolet (EUV) photoelectron spectroscopy of liquids with a single-order high harmonic. The distributions are Gaussian in all cases. Using the EUV and UV photoelectron spectra of solvated electrons, we succeeded in retrieving sharp electron kinetic energy distributions from the spectra broadened and energy shifted by inelastic scattering in liquids, overcoming an obstacle in ultrafast UV photoelectron spectroscopy of liquids. The method is demonstrated for the benchmark systems of charge transfer to solvent reaction and ultrafast internal conversion of hydrated electron from the first excited state.
Collapse
|
29
|
Riley JW, Wang B, Parkes MA, Fielding HH. Design and characterization of a recirculating liquid-microjet photoelectron spectrometer for multiphoton ultraviolet photoelectron spectroscopy. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2019; 90:083104. [PMID: 31472605 DOI: 10.1063/1.5099040] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Accepted: 07/20/2019] [Indexed: 06/10/2023]
Abstract
A new recirculating liquid-microjet photoelectron spectrometer for multiphoton ultraviolet photoelectron spectroscopy is described. A recirculating system is essential for studying samples that are only available in relatively small quantities. The reduction in background pressure when using the recirculating system compared to a liquid-nitrogen cold-trap results in a significant improvement in the quality of the photoelectron spectra. Moreover, the recirculating system results in a negligible streaming potential. The instrument design, operation, and characterization are described in detail, and its performance is illustrated by comparing a photoelectron spectrum of aqueous phenol recorded using the recirculating system with one recorded using a liquid nitrogen cold-trap.
Collapse
Affiliation(s)
- Jamie W Riley
- Department of Chemistry, University College London, 20 Gordon Street, London, WC1H 0AJ, United Kingdom
| | - Bingxing Wang
- Department of Chemistry, University College London, 20 Gordon Street, London, WC1H 0AJ, United Kingdom
| | - Michael A Parkes
- Department of Chemistry, University College London, 20 Gordon Street, London, WC1H 0AJ, United Kingdom
| | - Helen H Fielding
- Department of Chemistry, University College London, 20 Gordon Street, London, WC1H 0AJ, United Kingdom
| |
Collapse
|
30
|
Karashima S, Suzuki T. Charge-Transfer-to-Solvent Reaction in a Hydrophobic Tetrabutylammonium Iodide Molecular Layer in Aqueous Solution. J Phys Chem B 2019; 123:3769-3775. [PMID: 30827113 DOI: 10.1021/acs.jpcb.8b12210] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We present ultrafast photoelectron spectroscopy of the charge-transfer-to-solvent reaction in a segregated TBAI (tetrabutylammonium iodide) molecular layer in aqueous solution. The reaction times and electron binding energies of transient species vary with TBAI concentration from a very low value of 1 × 10-3 mol L-1, which is in contrast to NaI solution exhibiting no concentration (0.01-1.0 mol L-1) dependence. The result from soft X-ray N(1s) spectroscopy indicates that the photoelectron intensity in TBAI aqueous solution is about 70 times enhanced as compared to that in NH4Cl aqueous solution for an identical salt concentration, and TBA+ drags I- to the surface region. At high TBAI concentrations, electrons released from I- are trapped and held in the TBAI molecular layer owing to electrostatic attraction by TBA+.
Collapse
Affiliation(s)
- Shutaro Karashima
- Department of Chemistry, Graduate School of Science , Kyoto University , Kitashirakawa-Oiwakecho , Sakyo-Ku, Kyoto 606-8502 , Japan
| | - Toshinori Suzuki
- Department of Chemistry, Graduate School of Science , Kyoto University , Kitashirakawa-Oiwakecho , Sakyo-Ku, Kyoto 606-8502 , Japan
| |
Collapse
|
31
|
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
|
32
|
Almeida NMS, Pawłowski F, Ortiz JV, Miliordos E. Transition-metal solvated-electron precursors: diffuse and 3d electrons in V(NH3)0,±6. Phys Chem Chem Phys 2019; 21:7090-7097. [DOI: 10.1039/c8cp07420h] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Ground and excited electronic states of V(NH3)0,±6 complexes, investigated with ab initio electronic structure theory, consist of a V(NH3)62+ core with up to three electrons distributed over its periphery.
Collapse
Affiliation(s)
| | - Filip Pawłowski
- Department of Chemistry and Biochemistry
- Auburn University
- Auburn
- USA
| | | | | |
Collapse
|
33
|
UV-Driven Harmonic Generation for Time-Resolved Photoelectron Spectroscopy of Polyatomic Molecules. APPLIED SCIENCES-BASEL 2018. [DOI: 10.3390/app8101784] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
A single-order harmonic pulse in the vacuum-ultraviolet (VUV) is highly desirable for time-resolved photoelectron spectroscopy (TRPES) of polyatomic molecules. A high-power 9th harmonic of a Ti:sapphire laser (hv = 14 eV) is obtained using a UV driving laser at 270 nm (the 3rd harmonic). We describe our recent efforts to develop VUV TRPES combined with UV-driven harmonic generation, and present a few representative results from our recent TRPES studies.
Collapse
|
34
|
Coons MP, Herbert JM. Quantum chemistry in arbitrary dielectric environments: Theory and implementation of nonequilibrium Poisson boundary conditions and application to compute vertical ionization energies at the air/water interface. J Chem Phys 2018; 148:222834. [DOI: 10.1063/1.5023916] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Affiliation(s)
- Marc P. Coons
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, USA
| | - John M. Herbert
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, USA
| |
Collapse
|
35
|
Riley JW, Wang B, Woodhouse JL, Assmann M, Worth GA, Fielding HH. Unravelling the Role of an Aqueous Environment on the Electronic Structure and Ionization of Phenol Using Photoelectron Spectroscopy. J Phys Chem Lett 2018; 9:678-682. [PMID: 29356540 DOI: 10.1021/acs.jpclett.7b03310] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Water is the predominant medium for chemistry and biology, yet its role in determining how molecules respond to ultraviolet light is not well understood at the molecular level. Here, we combine gas-phase and liquid-microjet photoelectron spectroscopy to investigate how an aqueous environment influences the electronic structure and relaxation dynamics of phenol, a ubiquitous motif in many biologically relevant chromophores. The vertical ionization energies of electronically excited states are important quantities that govern the rates of charge-transfer reactions, and, in phenol, the vertical ionization energy of the first electronically excited state is found to be lowered by around 0.8 eV in aqueous solution. The initial relaxation dynamics following photoexcitation with ultraviolet light appear to be remarkably similar in the gas-phase and aqueous solution; however, in aqueous solution, we find evidence to suggest that solvated electrons are formed on an ultrafast time scale following photoexcitation just above the conical intersection between the first two excited electronic states.
Collapse
Affiliation(s)
- Jamie W Riley
- Department of Chemistry, University College London , 20 Gordon Street, London, WC1H 0AJ, United Kingdom
| | - Bingxing Wang
- Department of Chemistry, University College London , 20 Gordon Street, London, WC1H 0AJ, United Kingdom
| | - Joanne L Woodhouse
- Department of Chemistry, University College London , 20 Gordon Street, London, WC1H 0AJ, United Kingdom
| | - Mariana Assmann
- Department of Chemistry, University College London , 20 Gordon Street, London, WC1H 0AJ, United Kingdom
| | - Graham A Worth
- Department of Chemistry, University College London , 20 Gordon Street, London, WC1H 0AJ, United Kingdom
| | - Helen H Fielding
- Department of Chemistry, University College London , 20 Gordon Street, London, WC1H 0AJ, United Kingdom
| |
Collapse
|
36
|
Lifetimes and energetics of the first electronically excited states of NaH2O from time-resolved photoelectron imaging. Chem Phys Lett 2017. [DOI: 10.1016/j.cplett.2017.01.044] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
37
|
Farr EP, Zho CC, Challa JR, Schwartz BJ. Temperature dependence of the hydrated electron’s excited-state relaxation. II. Elucidating the relaxation mechanism through ultrafast transient absorption and stimulated emission spectroscopy. J Chem Phys 2017; 147:074504. [DOI: 10.1063/1.4985906] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Affiliation(s)
- Erik P. Farr
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095-1569, USA
| | - Chen-Chen Zho
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095-1569, USA
| | - Jagannadha R. Challa
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095-1569, USA
| | - Benjamin J. Schwartz
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095-1569, USA
| |
Collapse
|
38
|
Amanatidis S, Yoder BL, Signorell R. Low-energy photoelectron transmission through aerosol overlayers. J Chem Phys 2017; 146:224204. [PMID: 29166077 PMCID: PMC5469680 DOI: 10.1063/1.4983995] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2017] [Accepted: 05/08/2017] [Indexed: 11/14/2022] Open
Abstract
The transmission of low-energy (<1.8 eV) photoelectrons through the shell of core-shell aerosol particles is studied for liquid squalane, squalene, and di-ethyl-hexyl-sebacate shells. The photoelectrons are exclusively formed in the core of the particles by two-photon ionization. The total photoelectron yield recorded as a function of shell thicknesses (1-80 nm) shows a bi-exponential attenuation. For all substances, the damping parameter for shell thicknesses below 15 nm lies around 8 to 9 nm and is tentatively assigned to the electron attenuation length at electron kinetic energies of ≲1 eV. The significantly larger damping parameters for thick shells (>20 nm) are presumably a consequence of distorted core-shell structures. A first comparison of aerosol and traditional thin film overlayer methods is provided.
Collapse
Affiliation(s)
- Stavros Amanatidis
- Department of Chemistry and Applied Biosciences, Laboratory of Physical Chemistry, ETH Zürich, Vladimir-Prelog-Weg 2, CH-8093 Zürich, Switzerland
| | - Bruce L Yoder
- Department of Chemistry and Applied Biosciences, Laboratory of Physical Chemistry, ETH Zürich, Vladimir-Prelog-Weg 2, CH-8093 Zürich, Switzerland
| | - Ruth Signorell
- Department of Chemistry and Applied Biosciences, Laboratory of Physical Chemistry, ETH Zürich, Vladimir-Prelog-Weg 2, CH-8093 Zürich, Switzerland
| |
Collapse
|
39
|
Affiliation(s)
- John M. Herbert
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210
| | - Marc P. Coons
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210
| |
Collapse
|
40
|
Luckhaus D, Yamamoto YI, Suzuki T, Signorell R. Genuine binding energy of the hydrated electron. SCIENCE ADVANCES 2017; 3:e1603224. [PMID: 28508051 PMCID: PMC5409453 DOI: 10.1126/sciadv.1603224] [Citation(s) in RCA: 89] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Accepted: 03/02/2017] [Indexed: 05/24/2023]
Abstract
The unknown influence of inelastic and elastic scattering of slow electrons in water has made it difficult to clarify the role of the solvated electron in radiation chemistry and biology. We combine accurate scattering simulations with experimental photoemission spectroscopy of the hydrated electron in a liquid water microjet, with the aim of resolving ambiguities regarding the influence of electron scattering on binding energy spectra, photoelectron angular distributions, and probing depths. The scattering parameters used in the simulations are retrieved from independent photoemission experiments of water droplets. For the ground-state hydrated electron, we report genuine values devoid of scattering contributions for the vertical binding energy and the anisotropy parameter of 3.7 ± 0.1 eV and 0.6 ± 0.2, respectively. Our probing depths suggest that even vacuum ultraviolet probing is not particularly surface-selective. Our work demonstrates the importance of quantitative scattering simulations for a detailed analysis of key properties of the hydrated electron.
Collapse
Affiliation(s)
- David Luckhaus
- Laboratory of Physical Chemistry, Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 2, CH-8093 Zürich, Switzerland
| | - Yo-ichi Yamamoto
- Department of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwake-cho, Sakyo-Ku, Kyoto 606-8502, Japan
| | - Toshinori Suzuki
- Department of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwake-cho, Sakyo-Ku, Kyoto 606-8502, Japan
| | - Ruth Signorell
- Laboratory of Physical Chemistry, Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 2, CH-8093 Zürich, Switzerland
| |
Collapse
|
41
|
Okuyama H, Suzuki YI, Karashima S, Suzuki T. Charge-transfer-to-solvent reactions from I− to water, methanol, and ethanol studied by time-resolved photoelectron spectroscopy of liquids. J Chem Phys 2016; 145:074502. [PMID: 27544114 DOI: 10.1063/1.4960385] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- Haruki Okuyama
- Department of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwakecho, Sakyo-ku, Kyoto 606-8502, Japan
| | - Yoshi-Ichi Suzuki
- Department of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwakecho, Sakyo-ku, Kyoto 606-8502, Japan
- Faculty of Pharmaceutical Science, Health Sciences University of Hokkaido, 1757 Kanazawa, Tobetsucho, Ishikari, Hokkaido 061-0293, Japan
| | - Shutaro Karashima
- Department of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwakecho, Sakyo-ku, Kyoto 606-8502, Japan
| | - Toshinori Suzuki
- Department of Chemistry, Graduate School of Science, Kyoto University, Kitashirakawa-Oiwakecho, Sakyo-ku, Kyoto 606-8502, Japan
| |
Collapse
|
42
|
Coons MP, You ZQ, Herbert JM. The Hydrated Electron at the Surface of Neat Liquid Water Appears To Be Indistinguishable from the Bulk Species. J Am Chem Soc 2016; 138:10879-86. [DOI: 10.1021/jacs.6b06715] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Marc P. Coons
- Department of Chemistry and
Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States
| | - Zhi-Qiang You
- Department of Chemistry and
Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States
| | - John M. Herbert
- Department of Chemistry and
Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States
| |
Collapse
|