Femtosecond dissociation dynamics of core-excited molecular water

Brito, A. Naves de; Feifel, Raimund; Mocellin, Alexandra; Machado, A.B; Sundin, S.; Hjelte, I.; Sörensen, S. L.; Björneholm, Olle

doi:10.1016/s0009-2614(99)00693-4

Cited by 73 publications

(48 citation statements)

References 17 publications

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“…Other very recent work has inferred the rearrangement of atoms within a molecule during the HHG process, by comparing spectra of isotope-substituted (CH 4 , CD 4 ) molecules (26). This experiment is similar in character to past work where x-ray ionization could initiate molecular dynamics that could be monitored through core-hole spectroscopy (27,28). However, these techniques are limited in that initiation and measurement of the dynamics are necessarily coupled.…”

supporting

confidence: 65%

Monitoring molecular dynamics using coherent electrons from high harmonic generation

Wagner

Wüest²,

Christov³

et al. 2006

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

182

115

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We report a previously undescribed spectroscopic probe that makes use of electrons rescattered during the process of highorder harmonic generation. We excite coherent vibrations in SF 6 using impulsive stimulated Raman scattering with a short laser pulse. A second, more intense laser pulse generates high-order harmonics of the fundamental laser, at wavelengths of Ϸ20 -50 nm. The high-order harmonic yield is observed to oscillate, at frequencies corresponding to all of the Raman-active modes of SF6, with an asymmetric mode most visible. The data also show evidence of relaxation dynamics after impulsive excitation of the molecule. Theoretical modeling indicates that the high harmonic yield should be modulated by both Raman and infrared-active vibrational modes. Our results indicate that high harmonic generation is a very sensitive probe of vibrational dynamics and may yield more information simultaneously than conventional ultrafast spectroscopic techniques. Because the de Broglie wavelength of the recolliding electron is on the order of interatomic distances, i.e., Ϸ1.5 Å, small changes in the shape of the molecule lead to large changes in the high harmonic yield. This work therefore demonstrates a previously undescribed spectroscopic technique for probing ultrafast internal dynamics in molecules and, in particular, on the chemically important ground-state potential surface.spectroscopy ͉ ultrafast ͉ x-rays T he use of ultrafast light pulses to visualize chemical dynamics has advanced our fundamental understanding of chemical and biochemical processes, by providing a means of monitoring the motion of atoms within a molecule in real time (1, 2). This new field of femtochemistry has enabled the study of important processes such as the dynamics of molecular wave packets and the biochemical basis of vision (3), as well as proton transfer across membranes.Progress in this area of research has been driven by the development of new ultrashort-pulse light sources, as well as the development of new experimental techniques. Recent work has made use of sources of ultrafast extreme-UV (EUV) (4), x-ray (5, 6), and electron pulses (7, 8) as probes of ultrafast molecular and materials dynamics. These new probes can directly provide atomic-scale spatial resolution (e.g., electron and x-ray diffraction) or site-specific local order (e.g., photoelectron spectroscopy), providing the potential to directly observe chemical reactions in atomic-level detail as they occur. These new tools promise to provide a powerful new window into the microscopic world, particularly as the temporal resolution and energy range of these sources continues to improve.One recent area of research motivated by these goals is the generation of ultrashort EUV light pulses through the process of high-order harmonic generation (HHG) (9). HHG pushes traditional nonlinear optics to an extreme, by coherently combining many laser photons together to generate coherent beams that span from the UV to the kiloelectronvolt (1 eV ϭ 1.602 ϫ 10 Ϫ19 J) region of the spectru...

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supporting

confidence: 65%

Monitoring molecular dynamics using coherent electrons from high harmonic generation

Wagner

Wüest²,

Christov³

et al. 2006

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

182

115

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“…Excitation into antibonding orbitals leads to much larger deviations of the final state equilibrium geometries which is seen as greater broadening of the spectral features in comparison to excitations into non-bonding orbitals such as Rydberg states. Furthermore, excitation into the 4a 1 antibonding state leads to a final state potential energy curve which is dissociative where the hydrogen atom will be repelled with a kinetic energy depending on the initial nuclear position at the time of ionization (69)(70)(71).…”

Section: Fig 11mentioning

confidence: 99%

X-ray absorption spectroscopy and X-ray Raman scattering of water and ice; an experimental view

Nilsson

Nordlund

Waluyo

et al. 2010

Journal of Electron Spectroscopy and Related Phenomena

175

290

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Here we present a review of x-ray absorption spectroscopy and x-ray Raman scattering with the perspective to understand the spectra of water including changes with temperature, mass of the water molecule and presence of monovalent ions. The different detection schemes are discussed and it is concluded that transmission x-ray absorption measurements, using a small area where the thickness is uniform, and x-ray Raman scattering give the most reliable spectra. Different model systems are discussed such as the surface and bulk of ice and various adsorbed monolayer structures on metal surfaces.

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“…In the case of the core-excited H 2 O, for instance, the core-excited OH fragment has been shown to follow the O 1s→4a 1 excitation and then to relax by Auger decay. 33,34 …”

Section: Introductionmentioning

confidence: 99%

High-resolution inner-shell photoabsorption of the OH and OD free radicals

Stranges

Richter

Alagia

2002

The Journal of Chemical Physics

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The O 1s photoabsorption ~ion-yield! spectra of OH (2Pi ,v950) and OD (2Pi ,v950) radicals have been studied in the gas phase for the first time. Spectroscopic parameters for the O 1s!p excited 2S1 state of OH and OD, observed at ;525.8 eV, have been obtained from a Franck– Condon analysis comparing the spectra of both molecules. The lifetime width of this state has been measured as G5147611 meV and G515667 meV for OH and OD, respectively. Excellent quantitative agreement is found between the experimental spectroscopic parameters re , ve , and T0 , measured in this work for the 2S1 state and recent theoretical results obtained for OH by high-level ab initio calculations. The spectroscopic parameters predicted by the equivalent-core model are close to the experimental values within a few percent. This model therefore provides an accurate description of the lowest-lying excitation process in both OH and OD molecules

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Femtosecond dissociation dynamics of core-excited molecular water

Cited by 73 publications

References 17 publications

Monitoring molecular dynamics using coherent electrons from high harmonic generation

Monitoring molecular dynamics using coherent electrons from high harmonic generation

X-ray absorption spectroscopy and X-ray Raman scattering of water and ice; an experimental view

High-resolution inner-shell photoabsorption of the OH and OD free radicals

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