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First‐principles studies on the impact of proton disorder on physical properties of ice
Author(s) -
Wang Shaoqing
Publication year - 2012
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.24033
Subject(s) - dielectric , dipole , condensed matter physics , band gap , semiconductor , valence (chemistry) , proton , ice ih , polarization (electrochemistry) , materials science , chemistry , molecule , physics , optoelectronics , quantum mechanics , organic chemistry
The random occupancy of hydrogen atoms or proton disorder is the most unique feature of ice crystal. Taking the cubic Ic ice as an example, we study the impact of proton disorder on various physical properties by first‐principles calculation in density‐functional theory for the first time. Our results show that the dielectric polarization enhances the cohesion of H 2 O molecules, thus increases the bulk modulus of Ic ice. The shear elastic constants are more sensitive to dielectric polarization than the elastic constant of normal strain. Ic ice is a semiconductor with a wide direct bandgap of 5.54 eV. The disorder of electric dipole moments raises the valence bands and decreases the energy bandgap. The average dielectric constant is less affected by the disorder. The present conclusions also keep valid for the more common hexagonal Ih ice based on its similar local structure with Ic ice. © 2012 Wiley Periodicals, Inc.