Hydrogen bond vibrations of hydrogen-disordered ice

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Marco E. Ciriotti
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Hydrogen bond vibrations of hydrogen-disordered ice

Messaggio da Marco E. Ciriotti » mar 15 giu, 2021 16:48

▪ Yu, Xu-H., Qin, X.-L., Dong, X.-T., Cao, J.-W., Zhu, Xu-L., Wang, H.-C., Sun, Y.-Ju, Xu, Zi-X., Zhang, P. (2021): Studies of Hydrogen Bond Vibrations of Hydrogen-Disordered Ice Ic. Crystals, 11, 668.

The hydrogen-disordered structure of ice, Ic, makes it difficult to analyze the vibrational normal modes in the far-infrared region (i.e., the molecular translation band). To clarify the origin of the energy-splitting of hydrogen bond vibrations in this area, a 64-molecule supercell was constructed and calculated using first-principles density functional theory. The results were in good agreement with inelastic neutron scattering experiments and our previous study of a hydrogen-ordered ice Ic model. Assisted by analytic equations, we concluded that the origin of the two hydrogen bond peaks in real ice Ic is consistent with that of hydrogen-ordered ice Ic: the peaks originate from two kinds of normal mode vibration. We categorize the four peaks in the far-infrared region recorded from inelastic neutron scattering experiments as the acoustic peak, the superposition peak, the two-hydrogen bond peak and the four-hydrogen bond peak. We conclude that the existence of two intrinsic hydrogen bond vibration modes represents a general rule among the ice family, except ice X.
Marco E. Ciriotti

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