Suppression of X-ray-induced dissociation of H2O molecules in dense ice under pressure
نویسندگان
چکیده
We investigated molecular dissociation induced by 10-keV X-ray irradiation in dense ice at pressures up to 40 GPa at 300 K. The dissociation yield estimated from the oxygen K-edge X-ray Raman spectra, showed that the molecular dissociation was enhanced up to 14 GPa and gradually suppressed on further compression to 40 GPa. The molecular dissociation was detected for a rather narrow pressure span of 2-40 GPa by the X-ray spectroscopy. The pressure variation of the dissociation yield was similar to that observed in the electric conductivity of ice VII and likely interpreted in terms of proton mobility.
منابع مشابه
X-ray-induced Dissociation of H2O and Formation of an O2-H2 Compound at High Pressure
In this work we used inelastic X-ray scattering to study the high-pressure behavior of H2O. At lower pressures and low temperatures, X-ray Raman spectroscopy (XRS) is used for investigating water, ice Ih, ices II and IX. At higher pressures we discovered new radiation chemistry in the H2O system. A new compound composed of molecular oxygen and hydrogen was formed after X-ray irradiation of the ...
متن کاملPressure-induced dissociation of water molecules in ice VII
The neutron diffraction pattern of D2O ice was recently measured at pressures up to 52 GPa by Guthrie et al., who proposed an octahedral interstitial model for ice at pressures above 13 GPa to account for the deviation of the observed crystal structure from that of ice VII. In this article, the octahedral interstitial model was re-examined in terms of the interstitial occupancy and X-ray Raman ...
متن کاملSYNTHESIS, X-RAY CRYSTAL STRUCTURE AND IR STUDY OF NEW TRINUCLEAR, BASE CARBOXSYLATE COMPLEX OF [Cu3O(OAc)6(H2O)3]Cl.CH3OH.6H2O
The synthesis of [Cu3O(OAc)6(H2O)3]Cl.CH3OH.6H2O is described. The X-ray crystallographic study of thecomplex revealed an isosceles triangle of copper atoms with a triply bridging oxo atom nearly in the plane of thetriangle. The coordination sphere around each metal center is close to distorted octahedral and the central{Cu3(μ3-O)} core is planar. Every two copper atoms were connected to each o...
متن کاملThermal Desorption of Water-Ice in the Interstellar Medium
Water (H2O) ice is an important solid constituent of many astrophysical environments. To comprehend the role of such ices in the chemistry and evolution of dense molecular clouds and comets, it is necessary to understand the freeze-out, potential surface reactivity, and desorption mechanisms of such molecular systems. Consequently, there is a real need from within the astronomical modelling com...
متن کاملPhotochemistry of polycyclic aromatic hydrocarbons in cosmic water ice
Context. Mid-infrared emission features originating from polycyclic aromatic hydrocarbons (PAHs) are observed towards photon dominated regions in space. Towards dense clouds, however, these emission features are quenched. Observations of dense clouds show that many simple volatile molecules are frozen out on interstellar grains, forming thin layers of ice. Recently, observations have shown that...
متن کامل