TITLE

Mechanical and molecular properties of ice VIII from crystal-orbital ab initio calculations

AUTHOR(S)
Ojamäe, Lars; Hermansson, Kersti; Dovesi, Roberto; Roetti, Carla; Saunders, V. R.
PUB. DATE
February 1994
SOURCE
Journal of Chemical Physics;2/1/1994, Vol. 100 Issue 3, p2128
SOURCE TYPE
Academic Journal
DOC. TYPE
Article
ABSTRACT
The proton-ordered ice VIII structure has been investigated by ab initio periodic Hartree–Fock calculations in the pressure interval from 0 to 30 GPa using a 6-31G** basis set. The structure was optimized by energy-minimization at different volumes, and from the resulting energy vs volume relationship, the equation of state of ice VIII was derived. The variation of the structure, intramolecular geometry, Mulliken charges, electron density, Raman spectrum, and infrared stretching vibrations with varying pressure were investigated. The agreement with existing experimental data is generally good. Nearest-neighbor hydrogen-bonded O...O distances decrease from 2.88 to 2.57 Å as the pressure is increased from 0 to 30 GPa. For the same pressure range, the intramolecular OH bond increases from 0.951 to 0.955 Å (giving a drOH/dP value of 0.000 14 Å/GPA), the Mulliken charge on H increases from +0.386 to +0.452, the calculated bulk modulus increases from ∼25 to ∼160 GPa (corresponding experimental values are ∼25 at 2.4 GPa and ∼135 at 30 GPa), and the electron density redistribution is considerably enhanced. The frequency downshift of the OH stretching vibration varies from -200 cm-1 at 2.4 GPa to -500 cm-1 at 20 GPa; the corresponding experimental values are -300 and -650 cm-1. Electronic density-of-states diagrams are presented.
ACCESSION #
7610615

 

Related Articles

  • Evidence for the surface origin of point defects in ice: Control of interior proton activity by adsorbates. Devlin, J. Paul; Buch, Victoria // Journal of Chemical Physics;9/7/2007, Vol. 127 Issue 9, p091101 

    Spectroscopic studies are presented of H–D isotopic exchange in the interior of ice nanocrystals. The exchange process is dominated by ionic and orientational defects long viewed as governing the electrical properties of ice. A new finding that interior exchange rates can be controlled by...

  • �Symmetrical� phase and collective excitations in the proton system of ice. Ryzhkin, I. A. // Journal of Experimental & Theoretical Physics;Jun99, Vol. 88 Issue 6, p1208 

    A model of the ice proton system taking into account quantum-mechanical tunneling of protons along hydrogen bonds has been formulated and investigated. When the tunneling amplitude is small the quantum ground state of the proton system is degenerate, like the classical ground state. At higher...

  • A test of the intrinsic nature of the shallow proton traps in ice. Wooldridge, Paul J.; Devlin, J. Paul // Journal of Chemical Physics;4/1/1986, Vol. 84 Issue 7, p4111 

    Electron beam radiolysis of ice and the ion pair defects it generates in ice are discussed. The FI-IR spectra of thin films of ice are recorded both before and after irradiation. (AIP)

  • Investigation of Velocity Surface of Bulk Acoustic Waves for Proton-Exchanged LiNbO3 Crystal. Chen, G.; Zhang, X. R.; Cheng, J. C. // AIP Conference Proceedings;2003, Vol. 657 Issue 1, p1277 

    We calculate the velocity surface of bulk acoustic waves propagating in the YZ-, XY- and ZX- planes of proton-exchanged LiNbO3, based on the theory of acoustic wave in anisotropic solid with piezoelectricity. The calculation results show that the velocity change due to proton-exchange when the...

  • Optical constants of ice Ih crystal at terahertz frequencies. Zhang, Chun; Lee, Kwang-Su; Zhang, X.-C.; Wei, Xing; Shen, Y. R. // Applied Physics Letters;7/23/2001, Vol. 79 Issue 4 

    Terahertz time-domain spectroscopy was used to measure the refractive indices of Ih crystalline ice in the frequency range of 0.25–1.0 THz. With increasing frequency, the real part, n[sup ′], of the refractive index increases from 1.787 to 1.793 at 243 K, and the imaginary part,...

  • Characterization of ice crystals in clouds by simple mathematical expressions based on successive.. Wang, Pao K. // Journal of the Atmospheric Sciences;8/1/97, Vol. 54 Issue 15, p2035 

    Presents a study which used elementary mathematical functions to discuss the two-dimensional characterization of planar hexagonal ice crystals. Outline of the mathematical description of columnar crystals; Results of the study.

  • The theoretical basis for the parameterization of ice crystal habits: Growth by vapor deposition. Chen, Jen-Ping; Lamb, Dennis // Journal of the Atmospheric Sciences;5/1/94, Vol. 51 Issue 9, p1206 

    Analyzes surface kinetic and gas-phase diffusional effects which enable the specification of growth rates and habits of ice crystals. Factors determining the primary and secondary crystal habits; Application of adaptive parameterization in a microphysical model; Mass-dimension relationship in...

  • Did You Know???  // Junior Scholastic;4/10/2006, Vol. 108 Issue 16, p4 

    The article reports that the pictures sent from Saturn planet show plumes of ice crystal which indicates the presence of water over there.

  • Numerical simulation of three-dimensional unsteady flow past ice crystals. Wang, Pao K.; Ji, Wusheng // Journal of the Atmospheric Sciences;9/15/97, Vol. 54 Issue 18, p2261 

    Presents a study on the ice crystals in relation to flow fields. Application of a quadratic interpolation for convective kinematics (QUICK) scheme and a predictor-corrector method; Details on the ice crystals being fixed in orientation; Features of the flow passing of the crystals; Results of...

Share

Read the Article

Courtesy of THE LIBRARY OF VIRGINIA

Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics