Results 181 to 190 of about 272 (215)
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Hydrogen-Bond Symmetrization of δ -AlOOH
Chinese Physics Letters, 2017The ?-AlOOH can transport water into the deep mantle along cold subducting slab geotherm. We investigate the hydrogen-bond symmetrization behavior of ?-AlOOH under the relevant pressure-temperature condition of the lower mantle using ab initio molecular dynamics (MD). The static symmetrization pressure of 30.0 GPa can be reduced to 17.0 GPa at 300 K by
Duan Kang +7 more
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Proton double minimum potentials in symmetric hydrogen bonds
Journal of the Chemical Society D: Chemical Communications, 1971A wide series of hydrogen bonded cations (B1HB2)+, where B1 and B2 are different heterocyclic bases, have been characterised spectroscopically, and the proton potential appears to depend on the difference of the pK values of the bases.
R. Clements +3 more
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Ice under pressure: transition to symmetrical hydrogen bonds
The Journal of Physical Chemistry, 1983We have examined at a rudimentary level the quantum-mechanical many-body problem for coupled proton motions along hydrogen bonds in compressed ices. Four cases are considered: ice IC, ices VI1 and VIII, and the hypothetical planar "square ice". Soft mode calculations were carried out for each to help identify patterns of long-range proton order that ...
Frank H. Stillinger +1 more
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Inorganic Chemistry, 2012
A chelating ligand formed by deprotonation of 2-(2'-pyridyl)-2-propanol stabilizes a distorted trigonal bipyramidal geometry in a 16e(-) d(6) 5-coordinate iridium complex with the alkoxide acting as a π donor. Ambiphilic species such as AcOH bearing both nucleophilic and electrophilic functionality form adducts with the unsaturated iridium complex ...
Nathan D, Schley +4 more
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A chelating ligand formed by deprotonation of 2-(2'-pyridyl)-2-propanol stabilizes a distorted trigonal bipyramidal geometry in a 16e(-) d(6) 5-coordinate iridium complex with the alkoxide acting as a π donor. Ambiphilic species such as AcOH bearing both nucleophilic and electrophilic functionality form adducts with the unsaturated iridium complex ...
Nathan D, Schley +4 more
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Ab InitioInfrared Absorption Study of the Hydrogen-Bond Symmetrization in Ice
Physical Review Letters, 1998We computed from first principles the infrared spectrum of ice at high pressure in the molecular phases VIII and VII and in the symmetric phase X by performing Car-Parrinello molecular dynamics simulations and evaluating the electronic polarization by means of the Berry phase formulation.
BERNASCONI M +2 more
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Infrared absorption study of the hydrogen-bond symmetrization in ice to 110 GPa
Physical Review B, 1996Infrared measurements at room temperature have shown that the hydrogen-bond symmetrization occurs at 62.1 GPa in ice. The OH stretching frequency initially located at 3500 ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$ at ambient pressure falls toward zero around 60 GPa.
, Aoki +3 more
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Kink Pair in Hydrogen Bonded Systems with Symmetric Double-Well Potential
International Journal of Theoretical Physics, 2007zbMATH Open Web Interface contents unavailable due to conflicting licenses.
Cheng, Yuan-Fa, Huang, Liang
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Hydrogen incorporation in stishovite at high pressure and symmetric hydrogen bonding in δ-AlOOH
Earth and Planetary Science Letters, 2004Abstract First-principles calculations of stishovite (SiO2), δ-AlOOH, and stishovite–δ-AlOOH solid solutions reveal that coupled substitutions of Al3+ and H+ for Si4+ provide a means for dissolving significant amounts of hydrogen in stishovite under lower-mantle conditions. The enthalpy of solution is positive, decreasing in magnitude with increasing
Wendy R Panero, Lars P Stixrude
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Ionic force field of vibrational spectra of symmetrical hydrogen bonds
The Journal of Chemical Physics, 1986The ionic force field for analysis of the vibrational spectra of symmetrical hydrogen bonds, X–H–X, is described. The force field has a stretching force constant K and a force constant kc derived from the Coulombic force. One characteristic of this force field is that the frequency of the symmetric stretching vibration, νs, can be calculated from the ...
Yoshiki Matsui +2 more
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Symmetric hydrogen bond in a water-hydroxyl complex on Cu(110)
Physical Review B, 2010Water-hydroxyl complexes were produced on Cu(110) and characterized by a scanning tunneling microscope (STM) and first-principles calculations. A water molecule was brought to a fixed hydroxyl (OH) group in a controlled manner with the STM, and two kinds of hydrogen-bonded complexes were produced selectively.
T. Kumagai +6 more
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