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Ito Y, Kominato M, Nakashima Y, Ohshimo K, Misaizu F. Fragment imaging in the infrared photodissociation of the Ar-tagged protonated water clusters H 3O +-Ar and H +(H 2O) 2-Ar. Phys Chem Chem Phys 2023; 25:9404-9412. [PMID: 36928842 DOI: 10.1039/d3cp00469d] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/08/2023]
Abstract
Infrared photodissociation of protonated water clusters with an Ar atom, namely H3O+-Ar and H+(H2O)2-Ar, was investigated by an imaging technique for mass-selected ions, to reveal the intra- and intermolecular vibrational dynamics. The presented system has the advantage of achieving fragment ion images with the cluster size- and mode-selective photoexcitation of each OH stretching vibration. Translational energy distributions of photofragments were obtained from the images upon the excitation of the bound (νb) and free (νf) OH stretching vibrations. The energy fractions in the translational motion were compared between νbI and νfI in H3O+-Ar or between νbII and νfII in H+(H2O)2-Ar, where the labels "I" and "II" represent H3O+-Ar and H+(H2O)2-Ar, respectively. In H3O+-Ar, the νfI excitation exhibited a smaller translational energy than νbI. This result can be explained by the higher vibrational energy of νfI, which enabled it to produce bending (ν4) excited H3O+ fragments that should be favored according to the energy-gap model. In contrast to H3O+-Ar, the νbII excitation of an Ar-tagged H2O subunit and the νfII excitation of an untagged H2O subunit resulted in very similar translational energy distributions in H+(H2O)2-Ar. The similar energy fractions independent of the excited H2O subunits suggested that the νbII and νfII excited states relaxed into a common intermediate state, in which the vibrational energy was delocalized within the H2O-H+-H2O moiety. However, the translational energy distributions for H+(H2O)2-Ar did not agree with a statistical dissociation model, which implied another aspect of the process, that is, Ar dissociation via incomplete energy randomization in the whole H+(H2O)2-Ar cluster.
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Affiliation(s)
- Yuri Ito
- Department of Chemistry, Graduate School of Science, Tohoku University, 6-3 Aoba, Aramaki, Aoba-ku, Sendai 980-8578, Japan.
| | - Mizuhiro Kominato
- Department of Chemistry, Graduate School of Science, Tohoku University, 6-3 Aoba, Aramaki, Aoba-ku, Sendai 980-8578, Japan.
| | - Yuji Nakashima
- Department of Chemistry, Graduate School of Science, Tohoku University, 6-3 Aoba, Aramaki, Aoba-ku, Sendai 980-8578, Japan.
| | - Keijiro Ohshimo
- Department of Chemistry, Graduate School of Science, Tohoku University, 6-3 Aoba, Aramaki, Aoba-ku, Sendai 980-8578, Japan.
| | - Fuminori Misaizu
- Department of Chemistry, Graduate School of Science, Tohoku University, 6-3 Aoba, Aramaki, Aoba-ku, Sendai 980-8578, Japan.
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2
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Sofronov OO, Bakker HJ. Nature of hydrated proton vibrations revealed by nonlinear spectroscopy of acid water nanodroplets. Phys Chem Chem Phys 2020; 22:21334-21339. [PMID: 32936152 DOI: 10.1039/d0cp03137b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We use polarization-resolved femtosecond pump-probe spectroscopy to investigate the vibrations of hydrated protons in anionic (AOT) and cationic (CTAB/hexanol) reverse micelles in the frequency range 2000-3500 cm-1. For small AOT micelles the dominant proton hydration structure consists of H3O+ with two OH groups donating hydrogen bonds to water molecules, and one OH group donating a weaker hydrogen bond to sulfonate. For cationic reverse micelles, we find that the absorption at frequencies >2500 cm-1 is dominated by asymmetric proton-hydration structures in which one of the OH groups of H3O+ is more weakly hydrogen-bonded to water than the other two OH groups.
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Li C, Swanson JMJ. Understanding and Tracking the Excess Proton in Ab Initio Simulations; Insights from IR Spectra. J Phys Chem B 2020; 124:5696-5708. [PMID: 32515957 PMCID: PMC7448536 DOI: 10.1021/acs.jpcb.0c03615] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Proton transport in aqueous media is ubiquitously important in chemical and biological processes. Although ab initio molecular dynamics (AIMD) simulations have made great progress in characterizing proton transport, there has been a long-standing challenge in defining and tracking the excess proton, or more properly, the center of excess charge (CEC) created when a hydrogen nucleus distorts the electron distributions of water molecules in a delocalized and highly dynamic nature. Yet, defining (and biasing) such a CEC is essential when combining AIMD with enhanced sampling methods to calculate the relevant macroscopic properties via free-energy landscapes, which is the standard practice for most processes of interest. Several CEC formulas have been proposed and used, but none have yet been systematically tested or rigorously derived. In this paper, we show that the CEC can be used as a computational tool to disentangle IR features of the solvated excess proton from its surrounding solvent, and in turn, how correlating the features in the excess charge spectrum with the behavior of CEC in simulations enables a systematic evaluation of various CEC definitions. We present a new definition of CEC and show how it overcomes the limitations of those currently available both from a spectroscopic point of view and from a practical perspective of performance in enhanced sampling simulations.
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Affiliation(s)
- Chenghan Li
- Department of Chemistry, Chicago Center for Theoretical Chemistry, James Franck Institute, and Institute for Biophysical Dynamics, The University of Chicago, Chicago, Illinois 60637, United States
| | - Jessica M. J. Swanson
- Department of Chemistry, Biological Chemistry Program, and Center for Cell and Genome Science, The University of Utah, Salt Lake City, Utah 84112, United States
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4
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Sofronov OO, Bakker HJ. Vibrational Relaxation Dynamics of the Core and Outer Part of Proton-Hydration Clusters. J Phys Chem B 2019; 123:6222-6228. [PMID: 31265298 PMCID: PMC6661761 DOI: 10.1021/acs.jpcb.9b02067] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
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We study the ultrafast
relaxation dynamics of hydrated proton clusters
in acetonitrile using femtosecond mid-infrared pump-probe spectroscopy.
We observe a strong dependence of transient absorption dynamics on
the frequency of excitation. When we excite the OH vibrations with
frequencies ≤3100 cm–1, we observe an ultrafast
energy relaxation that leads to the heating of the local environment
of the proton. This response is assigned to the OH vibrations of the
water molecules in the core of the hydrated proton cluster. When we
excite with frequencies ≥3200 cm–1, we observe
a relatively slow vibrational relaxation with a T1 time constant ranging from 0.22 ± 0.04 ps at νex = 3200 cm–1 to 0.37 ± 0.02 ps at
νex = 3520 cm–1. We assign this
response to water molecules in the outer part of the hydrated proton
cluster.
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Affiliation(s)
| | - Huib J Bakker
- AMOLF , Science Park 104 , 1098 XG Amsterdam , The Netherlands
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5
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Sofronov OO, Bakker HJ. Energy Relaxation and Structural Dynamics of Protons in Water/DMSO Mixtures. J Phys Chem B 2018; 122:10005-10013. [PMID: 30351147 PMCID: PMC6216113 DOI: 10.1021/acs.jpcb.8b06938] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
Abstract
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We
investigate the structure and dynamics of proton solvation structures
in mixed water/dimethyl sulfoxide (DMSO) solvents using two-color
mid-infrared femtosecond pump–probe spectroscopy. At a water
fraction below 20%, protons are mainly solvated as (DMSO-H)+ and (DMSO-H)+-H2O structures. We find that
excitation of the OH-stretch vibration of the proton in (DMSO-H)+-H2O structures leads to an ultrafast contraction
of the hydrogen bond between (DMSO-H)+ and H2O. This excited state relaxes rapidly with T1 = 95 ± 10 fs and leads in part to a strong local heating
effect and in part to predissociation of the protonated cluster into
(DMSO-H)+ and water monomers.
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Affiliation(s)
| | - Huib J Bakker
- AMOLF , Science Park 104 , 1098 XG Amsterdam , The Netherlands
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6
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Biswas R, Carpenter W, Fournier JA, Voth GA, Tokmakoff A. IR spectral assignments for the hydrated excess proton in liquid water. J Chem Phys 2018; 146:154507. [PMID: 28433032 DOI: 10.1063/1.4980121] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The local environmental sensitivity of infrared (IR) spectroscopy to a hydrogen-bonding structure makes it a powerful tool for investigating the structure and dynamics of excess protons in water. Although of significant interest, the line broadening that results from the ultrafast evolution of different solvated proton-water structures makes the assignment of liquid-phase IR spectra a challenging task. In this work, we apply a normal mode analysis using density functional theory of thousands of proton-water clusters taken from reactive molecular dynamics trajectories of the latest generation multistate empirical valence bond proton model (MS-EVB 3.2). These calculations are used to obtain a vibrational density of states and IR spectral density, which are decomposed on the basis of solvated proton structure and the frequency dependent mode character. Decompositions are presented on the basis of the proton sharing parameter δ, often used to distinguish Eigen and Zundel species, the stretch and bend character of the modes, the mode delocalization, and the vibrational mode symmetry. We find there is a wide distribution of vibrational frequencies spanning 1200-3000 cm-1 for every local proton configuration, with the region 2000-2600 cm-1 being mostly governed by the distorted Eigen-like configuration. We find a continuous red shift of the special-pair O⋯H+⋯O stretching frequency, and an increase in the flanking water bending intensity with decreasing δ. Also, we find that the flanking water stretch mode of the Zundel-like species is strongly mixed with the flanking water bend, and the special pair proton oscillation band is strongly coupled with the bend modes of the central H5O2+moiety.
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Affiliation(s)
- Rajib Biswas
- Department of Chemistry, James Franck Institute, and Institute for Biophysical Dynamics, The University of Chicago, Chicago, Illinois 60637, USA
| | - William Carpenter
- Department of Chemistry, James Franck Institute, and Institute for Biophysical Dynamics, The University of Chicago, Chicago, Illinois 60637, USA
| | - Joseph A Fournier
- Department of Chemistry, James Franck Institute, and Institute for Biophysical Dynamics, The University of Chicago, Chicago, Illinois 60637, USA
| | - Gregory A Voth
- Department of Chemistry, James Franck Institute, and Institute for Biophysical Dynamics, The University of Chicago, Chicago, Illinois 60637, USA
| | - Andrei Tokmakoff
- Department of Chemistry, James Franck Institute, and Institute for Biophysical Dynamics, The University of Chicago, Chicago, Illinois 60637, USA
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7
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Vener MV, Chernyshov IY, Rykounov AA, Filarowski A. Structural and spectroscopic features of proton hydrates in the crystalline state. Solid-state DFT study on HCl and triflic acid hydrates. Mol Phys 2017. [DOI: 10.1080/00268976.2017.1380860] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- M. V. Vener
- Quantum Chemistry Department, Mendeleev University of Chemical Technology, Moscow, Russia
- Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences, Moscow, Russia
| | - I. Yu. Chernyshov
- Quantum Chemistry Department, Mendeleev University of Chemical Technology, Moscow, Russia
- Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences, Moscow, Russia
| | - A. A. Rykounov
- Theoretical Department, Russian Federal Nuclear Center – All-Russian Research Institute of Technical Physics (RFNC-VNIITF), Snezhinsk, Russia
| | - A. Filarowski
- Faculty of Chemistry, University of Wrocław, Wrocław, Poland
- Department of Physics, Industrial University of Tyumen, Tyumen, Russia
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8
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Gruzdev V, Korkin D, Mooney BP, Havelund JF, Møller IM, Thelen JJ. Controlled modification of biomolecules by ultrashort laser pulses in polar liquids. Sci Rep 2017; 7:5550. [PMID: 28717198 PMCID: PMC5514113 DOI: 10.1038/s41598-017-05761-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Accepted: 05/22/2017] [Indexed: 11/18/2022] Open
Abstract
Targeted chemical modification of peptides and proteins by laser pulses in a biologically relevant environment, i.e. aqueous solvent at room temperature, allows for accurate control of biological processes. However, the traditional laser methods of control of chemical reactions are applicable only to a small class of photosensitive biomolecules because of strong and ultrafast perturbations from biomolecule-solvent interactions. Here, we report excitation of harmonics of vibration modes of solvent molecules by femtosecond laser pulses to produce controlled chemical modifications of non-photosensitive peptides and proteins in polar liquids under room conditions. The principal modifications included lysine formylation and methionine sulfoxidation both of which occur with nearly 100% yield under atmospheric conditions. That modification occurred only if the laser irradiance exceeded certain threshold level. The threshold, type, and extent of the modifications were completely controlled by solvent composition, laser wavelength, and peak irradiance of ultrashort laser pulses. This approach is expected to assist in establishing rigorous control over a broad class of biological processes in cells and tissues at the molecular level.
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Affiliation(s)
- Vitaly Gruzdev
- Department of Mechanical and Aerospace Engineering, University of Missouri, Columbia, MO, 65211, USA.
| | - Dmitry Korkin
- Department of Computer Science, Bioinformatics and Computational Biology Program, Worcester Polytechnic Institute, Worcester, MA, 01609, USA
| | - Brian P Mooney
- Charles W Gehrke Proteomics Center, University of Missouri, Columbia, MO, 65211, USA.,Department of Biochemistry, University of Missouri, Columbia, MO, 65211, USA.,Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO, 65211, USA
| | - Jesper F Havelund
- Department of Molecular Biology and Genetics, Aarhus University, Forsøgsvej 1, DK-4200, Slagelse, Denmark.,Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, DK-5200, Odense M, Denmark
| | - Ian Max Møller
- Department of Molecular Biology and Genetics, Aarhus University, Forsøgsvej 1, DK-4200, Slagelse, Denmark
| | - Jay J Thelen
- Department of Biochemistry, University of Missouri, Columbia, MO, 65211, USA. .,Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO, 65211, USA.
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9
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Liu L, Lotze S, Bakker HJ. Vibrational and structural relaxation of hydrated protons in Nafion membranes. Chem Phys Lett 2017. [DOI: 10.1016/j.cplett.2016.10.062] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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