Počet záznamů: 1  

Spectroscopic Properties of Benzene at the Air-Ice Interface: A Combined Experimental-Computational Approach

  1. 1.
    0432612 - ÚOCHB 2015 RIV US eng J - Článek v odborném periodiku
    Kania, R. - Malongwe, J. K. - Nachtigallová, Dana - Krousko, J. - Gladich, I. - Roeselová, Martina - Heger, D. - Klán, P.
    Spectroscopic Properties of Benzene at the Air-Ice Interface: A Combined Experimental-Computational Approach.
    Journal of Physical Chemistry A. Roč. 118, č. 35 (2014), s. 7535-7547. ISSN 1089-5639. E-ISSN 1520-5215
    Grant CEP: GA ČR GAP208/12/1318; GA ČR(CZ) GAP208/10/1724; GA MŠMT(CZ) LH11021
    Grant ostatní: GA ČR(CZ) GAP503/10/0947; GA MŠk(CZ) LO1214; European Social Fund(XE) CZ.1.07/2.3.00/30.0037
    Institucionální podpora: RVO:61388963
    Klíčová slova: density functional theory * polycyclic aromatic hydrocarbons * atmospheric air/ice interfaces
    Kód oboru RIV: CF - Fyzikální chemie a teoretická chemie
    Impakt faktor: 2.693, rok: 2014

    A combined experimental and computational approach was used to study the spectroscopic properties of benzene at the ice-air interface at 253 and 77 K in comparison with its spectroscopic behavior in aqueous solutions. Benzene-contaminated ice samples were prepared either by shock-freezing of benzene aqueous solutions or by benzene vapor-deposition on pure ice grains and examined using UV diffuse reflectance and emission spectroscopies. Neither the absorption nor excitation nor emission spectra provided unambiguous evidence of benzene associates on the ice surface even at a higher surface coverage. Only a small increase in the fluorescence intensity in the region above 290 nm found experimentally might be associated with formation of benzene excimers perturbed by the interaction with the ice surface as shown by ADC(2) excited-state calculations. The benzene associates were found by MD simulations and ground-state DFT calculations, although not in the arrangement that corresponds to the excimer structures. Our experimental results dearly demonstrated that the energy of the S-0 -> S-1 electronic transition of benzene is not markedly affected by the phase change or the microenvironment at the ice-air interface and its absorption is limited to the wavelengths below 268 nm. Neither benzene interactions with the water molecules of ice nor the formation of dimers and microcrystals at the air-ice interface thus causes any substantial bathochromic shift in its absorption spectrum. Such a critical evaluation of the photophysical properties of organic contaminants of snow and ice is essential for predictions and modeling of chemical processes occurring in polar regions.
    Trvalý link: http://hdl.handle.net/11104/0237067

     
     
Počet záznamů: 1  

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