The structure of hydrogen bonds in ice is considered theoretically taking into account the quantum tunneling of protons along the bonds and the Coulomb interaction of protons of different bonds. It is shown that the width and height of the potential barrier become very small at sufficiently small ...
Here we analyse inelastic neutron-scattering spectra for the ice I solid phase of water, which provide evidence for the existence of two different kinds of hydrogen-bond, of different strengths, in the solid. A model in which strong and weak hydrogen-bonds in the ratio of about 2:1 are ...
The interpretation of X-ray absorption spectra of water and ice The changes in the X-ray Absorption Spectrum (XAS) of water upon formation of hydrogen bonds (H-bonds) are analyzed with the aid of Density Functional Theo... M Cavalleri,H Ogasawara,LGM Pettersson,... - 《Chemical Physics ...
In order to reproduce the measured phonon density of states, a new lattice dynamic model has been proposed that two interaction strengths among the H bonds in ice Ih (and ice Ic) associated with the proton configurations have to be assumed. These two force constants are randomly distributed ...
In ice, the crystalline lattice is dominated by a regular array of hydrogen bonds which space the water molecules farther apart than they are in liquid water. This accounts for water's decrease in density upon freezing. In other words, the presence of hydrogen bonds enables ice to float, ...
Experimental/ hydrogen bondsiceliquid structuremolecular configurationsneutron diffractionwater/ structural characteristicsH-bonded networkswatericemolecular configurationsThe molecular configurations of water molecules in the disordered condensed state are investigated by neutron diffraction. The results provide evidence...
Each amino acid residues (n th) of the polypeptide chain carbonyl oxygen and C-terminal direction of the first four residues (the first n +4 a) of the amide nitrogen to form hydrogen bonds. In a typical right-handed α-helix structure, the pitch of 0.54nm, each ring contains 3.6 amino...
(redirected fromHydrogen bonds) Thesaurus Medical Encyclopedia hydrogen bond n. A chemical bond in which a hydrogen atom of one molecule is attracted to an electronegative atom, especially a nitrogen, oxygen, or fluorine atom, usually of another molecule. ...
- Ice has an open structure in which each oxygen atom forms 2 hydrogen bonds in addition to its own 2 covalent bonds. - the 4 bonds are tetrahedrally arranged around the oxygen atom H Cl H Cl H Cl H Cl - When ice melts, many of they hydrogen bonds break, open structure collapses, ...
Experimental/ domains hydrogen bonds ice melting surface phase transformations surface structure X-ray diffraction/ hydrogen-bonding network surface I h ice surface premelting synchrotron X-radiation oxygen-forbidden reflections surface-sensitive X-ray diffraction pure hydrogen Bragg reflections prism surfaces ...