ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    facet.materialart.
    Unknown
    Ultrafast x-ray diffraction of transient molecular structures in solution (2005)
    American Association for the Advancement of Science (AAAS)
    Details
    Publication Date: 2005-07-16
    Description: We report direct structural evidence of the bridged radical (CH2ICH2.) in a polar solution, obtained using time-resolved liquid-phase x-ray diffraction. This transient intermediate has long been hypothesized to explain stereo-chemical control in many association and/or dissociation reactions involving haloalkanes. Ultrashort optical pulses were used to dissociate an iodine atom from the haloethane molecule (C2H4I2) dissolved in methanol, and the diffraction of picosecond x-ray pulses from a synchrotron supports the following structural dynamics, with approximately 0.01 angstrom spatial resolution and approximately 100 picosecond time resolution: The loss of one iodine atom from C2H4I2 leads to the C-I-C triangular geometry of CH2ICH2.. This transient C2H4I then binds to an iodine atom to form a new species, the C2H4I-I isomer, which eventually decays into C2H4 + I2. Solvent dynamics were also extracted from the data, revealing a change in the solvent cage geometry, heating, and thermal expansion.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Ihee, H -- Lorenc, M -- Kim, T K -- Kong, Q Y -- Cammarata, M -- Lee, J H -- Bratos, S -- Wulff, M -- New York, N.Y. -- Science. 2005 Aug 19;309(5738):1223-7. Epub 2005 Jul 14.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry and School of Molecular Science (BK21), Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 305-701, Republic of Korea. hyotcherl.ihee@kaist.ac.kr〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/16020695" target="_blank"〉PubMed〈/a〉
    Keywords: Computer Simulation ; Free Radicals ; Hydrocarbons, Iodinated/*chemistry ; Isomerism ; Methanol/chemistry ; Molecular Structure ; Scattering, Radiation ; Solutions ; Solvents/chemistry ; Synchrotrons ; Temperature ; Thermodynamics ; Time Factors ; X-Ray Diffraction/*methods ; X-Rays
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
    Published by American Association for the Advancement of Science (AAAS)
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 2
    Electronic Resource
    Electronic Resource
    Anisotropy of pump-probe absorption of the hydrated electron: A statistical model (1998)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 109 (1998), S. 9950-9957 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: A statistical model is presented to interpret the pump-probe absorption anisotropy of the hydrated electron. Its basic ingredient is the assumption of cascade-type deactivation processes between its excited p-states. The theory uses the correlation function formalism of nonlinear statistical mechanics. A number of technical problems are discussed: construction of a relaxation operator describing the cascade, solution of the corresponding Heisenberg equation of motion, calculation of various tensorial quantities, etc. According to this model, the presence of a cascade reduces the pump-probe dichroism, particularly if the p-state splitting is small. Very short cascade relaxation times of the order of 10 fs are required for that purpose. As the upper state of an s↔p transition is quasi-degenerate, the magic angle theories do not apply here. The similarity between the deactivation processes in excited electronic states of polyatomic molecules and of the hydrated electron is emphasized. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.477661
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Ultrafast infrared pump–probe spectroscopy of water: A theoretical description (1994)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 101 (1994), S. 4536-4546 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: A theory is developed to describe a recent infrared pump–probe experiment in water. This theory is a statistical theory, similar to those elaborated earlier to interpret ultraviolet and visible spectra. Nonlinear optical processes involved are analyzed in terms of four-time correlation functions of the electric dipole moment of the system and of the incident electric fields, respectively. An analytical expression for the transient infrared signal is presented. The observed spectral characteristics are attributed to a gradual thermalization of the initial, pump-prepared state. The substructure of the observed bands is interpreted. This experiment probes the kinetics of conversion of H-bonds of different lengths into each other.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.467441
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Isotropic Raman study of ultrarapid proton-transfer reactions in aqueous mixtures (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 803-809 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: A theory is presented to study the exchange broadening of isotropic Raman bands due to ultrarapid proton-transfer reactions. It represents a generalization of standard theories of Raman band profiles of nonreactive liquids. The variables describing the reaction are assumed to represent a dichotomic Markovian process. The spectral behavior of various AH/H2O mixtures is studied as a function of the exchange rate and the interplay of various band shaping mechanisms is discussed in detail. Finally, the potentialities of the Raman spectroscopy as a tool to measure the rate constant are critically assessed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451288
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    A computer-simulation study of hydrophobic hydration of rare gases and of methane. I. Thermodynamic and structural properties (1991)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 95 (1991), S. 3643-3648 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: A theory is proposed to study the hydrophobic hydration of rare gases and methane in water. The Ostwald absorption coefficient γ, the hydration energy ΔE, and entropy ΔS are calculated by combining large-scale molecular-dynamics simulations and test-particle methods. The convergence of calculations is checked with particular care. The structure of the first two hydration shells is analyzed in terms of appropriate pair distribution functions. The picture conveyed by this theory is compared to that provided by the early work.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.460815
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    The statistical mechanics of the ionic equilibrium of water: A computer simulation study (1988)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 88 (1988), S. 5850-5856 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: A theory is presented to study the ionic equilibrium of water. Its equilibrium constant is expressed in terms of the chemical potentials of H2O, H3O+, and HO− and is calculated by combining molecular dynamics and test particle methods. Intermolecular potentials are studied in detail. The theory predicts a pH of a correct order of magnitude. Polarization effects are surprisingly large; both the polarization of water molecules by the ion and the backpolarization of strong H bonds around the ion by water molecules play an important role and dominate the process under investigation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.454547
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Raman spectroscopy of fast pre-reactive, reactive, and post-reactive molecular motions in liquids (1989)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 90 (1989), S. 7022-7029 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: A theory is presented to study the effect on the isotropic Raman spectra of pre-reactive, reactive, and post-reactive molecular motions in the case of fast conformational changes. The reaction dynamics is pictured as a diffusion along the reaction coordinate and is supposed to obey a one-dimensional Smoluchowski equation. The resulting correlation functions exhibit several modes, some of which are generated by pre-reactive and post-reactive processes. Their spectral manifestation is studied in detail.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.456228
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Subpicosecond transient infrared spectroscopy of water: A theoretical description (1995)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 103 (1995), S. 4887-4893 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The pump–probe response of water in infrared is examined theoretically at time scales of the order of 100 fs; these times scales are characteristic of spectral diffusion. The theory is a statistical theory using correlation function description of the nonlinear optical processes involved. An analytical expression for the transient infrared signal is presented, and the corresponding time- and frequency-resolved spectra are discussed. Real time shifts of spectral bands, preceded by a redistribution of their intensities, are predicted. Physical interpretation of these findings is proposed, corroborated by the help of simple models. The intrinsic interest of this time domain is emphasized. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.470624
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    A Fokker-Planck study of Raman band shapes of chemically reactive liquids: Comparison of phenomenological models
    Amsterdam : Elsevier
    Journal of Molecular Liquids 43 (1989), S. 93-100 
    Details
    ISSN: 0167-7322
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/0167-7322(89)80009-1
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Raman investigation of rapid chemical reactions in liquids
    Amsterdam : Elsevier
    Journal of Molecular Liquids 36 (1987), S. 185-204 
    Details
    ISSN: 0167-7322
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/0167-7322(87)80039-9
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...