Ultrafast vibrational predissociation of hydrogen bonds: Mode selective infrared photochemistry in liquids

Graener, H.; Ye, T. Q.; Laubereau, A.

doi:10.1063/1.457652

Cited by 106 publications

(71 citation statements)

References 12 publications

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“…17 At this point it is important to note that there are three relevant time scales in the experiment: ͑i͒ the vibrational lifetime T 1 , ͑ii͒ the onset time of the level L, i.e., the time between vibrational relaxation and the change in transmission hereby caused ͓considered instantaneous in our calculations, but not necessarily so ͑see below͔͒, and ͑iii͒ the slow relaxation time of this last effect ͑the observed offset of the transmission is constant for 1 ns after vibrational relaxation, but has faded when the next pulse pair travels through the sample ͑after Ϸ1 s͒. Similar double relaxation effects have been observed before for fluids, 15,28 but not in vibrational relaxation experiments on surface hydroxyls.…”

Section: Resultssupporting

confidence: 61%

Fast energy delocalization upon vibrational relaxation of a deuterated zeolite surface hydroxyl

Bonn

Brugmans

Kleyn

et al. 1995

The Journal of Chemical Physics

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. (1995). Fast energy delocalization upon vibrational relaxation of a deuterated zeolite surface hydroxyl. Chemical Physics, 102(5), 2181-2185. DOI: 10.1063/1.468740 General rightsCopyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.• Users may download and print one copy of any publication from the public portal for the purpose of private study or research.• You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal ? Take down policyIf you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. In this time-resolved study of vibrational dynamics of deuterated surface hydroxyls at acid sites in the zeolite Mordenite, we investigate the O-D T 1 vibrational lifetime and transient band shifts. It is shown that after infrared excitation of the stretching mode of a surface hydroxyl, the excess energy is rapidly distributed over delocalized low-energy lattice modes upon de-excitation. This is asserted from the observation that nonexcited hydroxyls are perturbed by the relaxation of their excited counterparts immediately after this relaxation. This observation can be made owing to better resolution in transient transmission spectroscopy obtained by deuteration of the surface hydroxyls. This assignment allows for accurate estimates of lattice temperatures after relaxation of the vibration. Further, from the observation that the vibrational lifetime is dependent on frequency ͑increasing from 25 to 70 ps with increasing frequency͒, it is concluded that the deuterated acidic protons are hydrogen bonded to lattice oxygen atoms in the zeolite.

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Section: Resultssupporting

confidence: 61%

Fast energy delocalization upon vibrational relaxation of a deuterated zeolite surface hydroxyl

Bonn

Brugmans

Kleyn

et al. 1995

The Journal of Chemical Physics

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“…The bands at 3,530 and 3,690 cm Ϫ1 cannot represent the symmetric and asymmetric OOH stretching modes of H 2 O, because then they would not have been observed for 1 H 2 HO. Instead, these bands represent the vibration of a hydrogen-bonded OOH group ( b ϭ 3,530 cm Ϫ1 ) and a non-hydrogen-bonded OOH group ( f ϭ 3,690 cm Ϫ1 ) (14,15). The absorption of the band at b is much stronger than the band at f , because the cross section of the OOH stretch vibration increases (by a factor of Ϸ10) upon hydrogen-bond formation.…”

Section: Resultsmentioning

confidence: 99%

Dynamics of confined water molecules

Gilijamse

Lock

Bakker

2005

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

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We present femtosecond midinfrared pump-probe measurements of the molecular motion and energy-transfer dynamics of a water molecule that is enclosed by acetone molecules. These confined water molecules show hydrogen-bond and orientational dynamics that are much slower than in bulk liquid water. This behavior is surprising because the hydrogen bonds to the CAO groups of the acetone molecules are weaker than the hydrogen bonds in bulk water. The energy transfer between the OOH groups of the confined water molecules has a time constant of 1.3 ؎ 0.2 ps, which is >20 times slower than in bulk water. We find that this energy transfer is governed completely by the rate at which hydrogen bonds are broken and reformed, and we identify the short-lived molecular complex that forms the transition state of this process.hydrogen bonding ͉ infrared pump-probe spectroscopy ͉ energy transfer W ater plays an essential role in many chemical and biological processes. Over the last decades, this notion has motivated a lot of work on the dynamical properties of bulk liquid water (1-7). However, the role of water in (bio)chemical processes is often played by a limited number of water molecules in a strongly restricted molecular environment. For example, the stability, structure, and biological function of proteins are largely determined by only a few surrounding layers of water molecules (8). When the water molecules participate directly in a reaction, the number of involved water molecules is even smaller. For example, the proton-pumping function of bacteriorhodopsin involves changes of the hydrogen network that is formed by particular amino acids of the protein and only a few confined water molecules (9-12).Recently, the dynamics of water in restricted environments was studied by comparing the spectral dynamics of an optically excited probe molecule embedded in a hydrated (bio)molecule with the spectral dynamics of the same probe molecule in bulk water (13). The spectral dynamics reflect the collective rearrangement of the solvating water, and were found to be much slower within the hydrated (bio)molecule than in bulk water. In this article, we present a study of the hydrogen-bond and energy-transfer dynamics of individual H 2 O and 1 H 2 HO molecules in a confined environment. In this study, we probed the dynamics of the water molecules directly with femtosecond midinfrared laser pulses that are resonant with the OOH stretch vibrations. Experimental MethodsThe system of confined water molecules is prepared by dissolving water (0.4 mol͞liter) in a mixture of acetone (4.0 mol͞liter) and CCl 4 . The structures that are formed in this mixture have a polar internal part consisting of an enclosed water molecule forming hydrogen bonds to the CAO groups of a few surrounding acetone molecules, and an apolar external part formed by the methyl groups of the acetone molecules. The favorable interaction between the methyl groups and the CCl 4 molecules allows these structures to enter the apolar CCl 4 matrix. The molecular ratio of H 2 O͞aceton...

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“…This process is analogous to the theoretically predicted and experimentally observed VER in alcohols, where energy transfer directly to the hydrogen bond leads to its subsequent rupture. [27][28][29][30][31][32][33] The OH-stretching mode dynamics in heavy water has also been studied by an IR pump visible probe pulse technique. 2,23 In this method, a femtosecond IR pump pulse excites the vibrational transition while the response of the system is monitored via spontaneous Raman scattering induced by a visible probe pulse.…”

Section: Introductionmentioning

confidence: 99%

Hydrogen Bonding and Vibrational Energy Relaxation in Water−Acetonitrile Mixtures

et al. 2004

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We present a study of the effect of hydrogen bonding on vibrational energy relaxation of the OH-stretching mode in pure water and in water-acetonitrile mixtures. The extent of hydrogen bonding is controlled by dissolving water at various concentrations in acetonitrile. Infrared frequency-resolved pump-probe measurements were used to determine the relative abundance of hydrogen-bonded versus non-hydrogen-bonded OH bonds in water-acetonitrile mixtures. Our data show that the main pathway for vibrational relaxation of the OH-stretching mode in pure water involves the overtone of the bending mode. Hydrogen bonding is found to accelerate the population relaxation from 3 ps in dilute solutions to 700 fs in neat water, as a result of increasing overlap between donor and acceptor modes. Hydroxyl groups that initially are not hydrogen bonded have two relaxation pathways: by direct nonresonant relaxation to the bending mode with a time constant of 12 ps or by making a hydrogen bond to a neighboring water molecule first (∼2 ps) and then relaxing as a hydrogen-bonded OH oscillator.

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Ultrafast vibrational predissociation of hydrogen bonds: Mode selective infrared photochemistry in liquids

Cited by 106 publications

References 12 publications

Fast energy delocalization upon vibrational relaxation of a deuterated zeolite surface hydroxyl

Fast energy delocalization upon vibrational relaxation of a deuterated zeolite surface hydroxyl

Dynamics of confined water molecules

Hydrogen Bonding and Vibrational Energy Relaxation in Water−Acetonitrile Mixtures

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