Probing dynamics of complex molecular systems with ultrafast 2D IR vibrational echo spectroscopy

Finkelstein, Ilya J.; Zheng, Junrong; Ishikawa, Hiromasa; Kim, Seongheun; Kwak, Kyungwon; Fayer, M. D.

doi:10.1039/b618158a

Cited by 91 publications

(152 citation statements)

References 114 publications

(255 reference statements)

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“…The structural evolution (frequency changes) is reflected in the changes of peak shape of the 2D IR spectra. The 2D IR vibrational echo experiments have been reviewed recently (23,32,33).…”

Section: Resultsmentioning

confidence: 99%

Hydrogen bond dynamics in aqueous NaBr solutions

Park

Fayer

2007

Proc. Natl. Acad. Sci. U.S.A.

294

403

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Hydrogen bond dynamics of water in NaBr solutions are studied by using ultrafast 2D IR vibrational echo spectroscopy and polarization-selective IR pump-probe experiments. The hydrogen bond structural dynamics are observed by measuring spectral diffusion of the OD stretching mode of dilute HOD in H2O in a series of high concentration aqueous NaBr solutions with 2D IR vibrational echo spectroscopy. The time evolution of the 2D IR spectra yields frequency-frequency correlation functions, which permit quantitative comparisons of the influence of NaBr concentration on the hydrogen bond dynamics. The results show that the global rearrangement of the hydrogen bond structure, which is represented by the slowest component of the spectral diffusion, slows, and its time constant increases from 1.7 to 4.8 ps as the NaBr concentration increases from pure water to Ϸ6 M NaBr. Orientational relaxation is analyzed with a wobbling-in-a-cone model describing restricted orientational diffusion that is followed by complete orientational randomization described as jump reorientation. The slowest component of the orientational relaxation increases from 2.6 ps (pure water) to 6.7 ps (Ϸ6 M NaBr). Vibrational population relaxation of the OD stretch also slows significantly as the NaBr concentration increases.ultrafast 2D IR spectroscopy ͉ water dynamics in ionic solutions W ater plays an important role in chemical and biological processes. In aqueous solutions, water molecules dissolve ionic compounds, charged chemical species, and biomolecules by forming hydration shells (layers) around them. Pure water undergoes rapid structural evolution of the hydrogen bond network that is responsible for water's unique properties (1). A question of fundamental importance is how the dynamics of water in the immediate vicinity of an ion or ionic group differ from those of pure water. For monatomic ions, molecular ions, charged groups of large molecules, or charged amino acids on the surfaces of proteins, the basic structure of hydration shells is determined by ion-dipole interactions between water molecules and the charged group (2, 3). Such ion-dipole interactions will influence both the structure and dynamics of water in the proximity of ions. Water dynamics in ion hydration shells play a significant role in the nature of systems such as proteins and micelles (3) and in processes such as ion transport through transmembrane proteins (4).Over the last several years, the application of ultrafast IR vibrational echo spectroscopy (5, 6), particularly 2D IR vibrational echo experiments, (7, 8) combined with molecular dynamics (MD) simulations (9-12) have greatly enhanced understanding of the hydrogen bond dynamics in pure water. These experiments directly examine the dynamics of water rather than study the indirect influence of water dynamics on a probe molecule (13). The ultrafast 2D IR vibrational echo experiments on water (7, 8) and other hydrogen-bonded systems (14) build upon earlier IR pump-probe experiments that have been extensively used to study ...

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“…The structural evolution (frequency changes) is reflected in the changes of peak shape of the 2D IR spectra. The 2D IR vibrational echo experiments have been reviewed recently (23,32,33).…”

Section: Resultsmentioning

confidence: 99%

Hydrogen bond dynamics in aqueous NaBr solutions

Park

Fayer

2007

Proc. Natl. Acad. Sci. U.S.A.

294

403

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“…Its structures and conformations are displayed in Figure 1. This molecule has several advantages to serve as the model system for the study; (1) it is small enough that the current ab initio calculations can relatively precisely predict many of its molecular properties; (2) it has several possible conformations; (3) it has many typical vibrational groups, for example, CdCÀH, CÀCÀH, CtN, CdC, CdO, and CÀO; (4) these vibrational groups cover all of the molecular space, and therefore, it is possible that the threedimensional conformations of this molecule can be obtained by investigating the vibrations of these groups; and (5) these vibrational groups covers a big vibrational frequency range (>2000 cm À1 ) and a big vibrational spatial separation (more than three chemical bonds), which allows us to explore the sensitivity and potential of our approach.…”

Section: Introductionmentioning

confidence: 99%

Mapping Molecular Conformations with Multiple-Mode Two-Dimensional Infrared Spectroscopy

Bian

Wen

et al. 2011

J. Phys. Chem. A

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The multiple-mode two-dimensional infrared (2D-IR) spectrum in a broad frequency range from 1000 to 3200 cm−1 of a 1-cyanovinyl acetate solution in CCl4 is reported. By analyzing its relative orientations of the transition dipole moments of normal modes that cover vibrations of all chemical bonds, the three-dimensional molecular conformations and their population distributions of 1-cyanovinyl acetate are obtained, with the aid of quantum chemistry calculations that translate the experimental transition dipole moment cross angles into the cross angles among chemical bonds.

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“…1,2 The unique value of IR spectroscopy becomes more transparent with the rapid development of various multidimensional techniques in recent years. [3][4][5][6][7] For condensed phase applications, however, the interpretation of IR spectra is not always straightforward, which highlights the importance of developing effective computational techniques that can compute linear and nonlinear IR spectra in complex molecular systems.…”

Section: Introductionmentioning

confidence: 99%

The vibrational spectra of protonated water clusters: A benchmark for self-consistent-charge density-functional tight binding

Cui

2007

The Journal of Chemical Physics

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The vibrational spectra of protonated water clusters: A benchmark for selfconsistent-charge density-functional tight binding AbstractProton transfers are involved in many chemical processes in solution and in biological systems. Although water molecules have been known to transiently facilitate proton transfers, the possibility that water molecules may serve as the "storage site" for proton in biological systems has only been raised in recent years. To characterize the structural and possibly the dynamic nature of these protonated water clusters, it is important to use effective computational techniques to properly interpret experimental spectroscopic measurements of condensed phase systems. Bearing this goal in mind, we systematically benchmark the self-consistent-charge density-functional tight-binding �SCC-DFTB� method for the description of vibrational spectra of protonated water clusters in the gas phase, which became available only recently with infrared multiphoton photodissociation and infrared predissociation spectroscopic experiments. It is found that SCC-DFTB qualitatively reproduces the important features in the vibrational spectra of protonated water clusters, especially concerning the characteristic signatures of clusters of various sizes. In agreement with recent ab initio molecular dynamics studies, it is found that dynamical effects play an important role in determining the vibrational properties of these water clusters. Considering computational efficiency, these benchmark calculations suggest that the SCC-DFTB/molecular mechanical approach can be an effective tool for probing the structural and dynamic features of protonated water molecules in biomolecular systems. The vibrational spectra of protonated water clusters: A benchmark for self-consistent-charge density-functional tight binding Proton transfers are involved in many chemical processes in solution and in biological systems. Although water molecules have been known to transiently facilitate proton transfers, the possibility that water molecules may serve as the "storage site" for proton in biological systems has only been raised in recent years. To characterize the structural and possibly the dynamic nature of these protonated water clusters, it is important to use effective computational techniques to properly interpret experimental spectroscopic measurements of condensed phase systems. Bearing this goal in mind, we systematically benchmark the self-consistent-charge density-functional tight-binding ͑SCC-DFTB͒ method for the description of vibrational spectra of protonated water clusters in the gas phase, which became available only recently with infrared multiphoton photodissociation and infrared predissociation spectroscopic experiments. It is found that SCC-DFTB qualitatively reproduces the important features in the vibrational spectra of protonated water clusters, especially concerning the characteristic signatures of clusters of various sizes. In agreement with recent ab initio molecular dynamics studies, it is found that dynamic...

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Probing dynamics of complex molecular systems with ultrafast 2D IR vibrational echo spectroscopy

Cited by 91 publications

References 114 publications

Hydrogen bond dynamics in aqueous NaBr solutions

Hydrogen bond dynamics in aqueous NaBr solutions

Mapping Molecular Conformations with Multiple-Mode Two-Dimensional Infrared Spectroscopy

The vibrational spectra of protonated water clusters: A benchmark for self-consistent-charge density-functional tight binding

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