Charvat, A. and Stasicki, Boleslaw and Abel, Bernd (2006) Product screening of fast reactions in IR-laser-heated liquid water filaments in vacuum by mass spectrometry. The Journal of Physical Chemistry A, 110 (9), pp. 3297-3306. American Chemical Society. DOI: 10.1021/jp055165e.
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In the present article a novel approach for rapid product screening of fast reactions in IR-laser-heated liquid microbeams in a vacuum is highlighted. From absorbed energies, a shock wave analysis, high-speed laser stroboscopy, and thermodynamic data of high-temperature water the enthalpy, temperature, density, pressure, and the reaction time window for the hot water filament could be characterized. The experimental conditions (30 kbar, 1750 K, density ∼1 g/cm3) present during the lifetime of the filament (20-30 ns) were extreme and provided a unique environment for high-temperature water chemistry. For the probe of the reaction products liquid beam desorption mass spectrometry was employed. A decisive feature of the technique is that ionic species, as well as neutral products and intermediates may be detected (neutrals as protonated aggregates) via time-of-flight mass spectrometry without any additional ionization laser. After the explosive disintegration of the superheated beam, high-temperature water reactions are efficiently quenched via expansion and evaporative cooling. For first exploratory experiments for chemistry in ultrahigh-temperature, -pressure and -density water, we have chosen resorcinol as a benchmark system, simple enough and well studied in high-temperature water environments much below 1000 K. Contrary to oxidation reactions usually present under less extreme and dense supercritical conditions, we have observed hydration and little H-atom abstraction during the narrow time window of the experiment. Small amounts of radicals but no ionic intermediates other than simple proton adducts were detected. The experimental findings are discussed in terms of the energetic and dense environment and the small time window for reaction, and they provide firm evidence for additional thermal reaction channels in extreme molecular environments.
|Additional Information:||Published on Web 02/10/2006|
|Title:||Product screening of fast reactions in IR-laser-heated liquid water filaments in vacuum by mass spectrometry|
|Journal or Publication Title:||The Journal of Physical Chemistry A|
|In ISI Web of Science:||Yes|
|Page Range:||pp. 3297-3306|
|Publisher:||American Chemical Society|
|Keywords:||high-speed laser stroboscopy, high-temperature water environments|
|HGF - Research field:||Aeronautics, Space and Transport (old)|
|HGF - Program:||Aeronautics|
|HGF - Program Themes:||Aircraft Research|
|DLR - Research area:||Aeronautics|
|DLR - Program:||L AR - Aircraft Research|
|DLR - Research theme (Project):||L - Flight Physics|
|Institutes and Institutions:||Institute of Aerodynamics and Flow Technology > Experimental Methods|
|Deposited By:||Ilka Micknaus|
|Deposited On:||21 Jun 2006|
|Last Modified:||27 Apr 2009 02:56|
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