Second-order many-body perturbation and coupled-cluster singles and doubles study of ice VIII
Kandis Gilliard1, Olaseni Sode2, So Hirata1
1Department of Chemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801, USA.
Abstract:
The structure, equation of state, IR, Raman, and inelastic neutron scattering (INS) spectra of high-pressure, proton-ordered phase VIII of ice are calculated by the second-order many-body perturbation and coupled-cluster singles and doubles methods. Nearly all the observed features of the pressure-dependence of the structures and spectra are reproduced computationally up to 60 GPa insofar as the anharmonic effects can be neglected. The calculations display no sign of the hypothetical isostructural transition in 2-3 GPa to phase VIII('), the existence of which has been a matter of controversy for over a decade, while they do not contradict the interpretation of the spectral anomaly at 10-14 GPa as a precursor of the VIII-X phase transition. The calculated INS spectra correct a systematic error in the peak positions of the observed spectra.
Related Concept Videos
02:58Crystal Field Theory - Octahedral Complexes
To explain the observed behavior of transition metal complexes (such as colors), a model involving electrostatic interactions between the electrons from the ligands and the electrons in the unhybridized d orbitals of the central metal atom has been developed. This electrostatic model is crystal field theory (CFT). It helps to understand, interpret, and predict the colors, magnetic behavior, and some structures of coordination compounds of transition metals.
CFT focuses on...
03:35Hybridization of Atomic Orbitals II
03:51Molecular Orbital Theory II
01:24Van der Waals Interactions
02:54Molecular and Ionic Solids
Molecular Solids
Molecular crystalline solids, such as ice, sucrose (table sugar), and iodine, are solids that are composed of neutral molecules as their constituent units. These molecules are held together by weak intermolecular forces such as London dispersion forces, dipole-dipole interactions, or hydrogen bonds, which...
02:46Crystal Field Theory - Tetrahedral and Square Planar Complexes
Crystal field theory (CFT) is applicable to molecules in geometries other than octahedral. In octahedral complexes, the lobes of the dx2−y2 and dz2 orbitals point directly at the ligands. For tetrahedral complexes, the d orbitals remain in place, but with only four ligands located between the axes. None of the orbitals points directly at the tetrahedral ligands. However, the dx2−y2 and dz2 orbitals (along the Cartesian axes) overlap with the ligands less than...