We report fundamental progress in the description of an archetypical hydrogen-bonded system: H(2)O-ice. We calculated by first principles the ice VII-VIII phase boundary, an order-disorder phase boundary, by performing a complete sampling of configurations in a 16-molecule supercell. Vibrational effects are included within quasiharmonic theory. Several important features were successfully described: negative Clapeyron slope, isotope effect, and nearly-constant T(c) at low pressures. The equation of state was very well described below 40 GPa. Inclusion of tunneling effects and increase of supercell size should decrease the remaining discrepancies, i.e., the overestimation of volume above similar to 40 GPa and the underestimation of T(c).

Order-disorder phase boundary between ice VII and VIII obtained by first principles / Umemoto, K.; Wentzcovitch, R. M.; de Gironcoli, S.; Baroni, S.. - In: CHEMICAL PHYSICS LETTERS. - ISSN 0009-2614. - 499:4-6(2010), pp. 236-240. [10.1016/j.cplett.2010.09.065]

Order-disorder phase boundary between ice VII and VIII obtained by first principles

de Gironcoli, S.;Baroni, S.
2010-01-01

Abstract

We report fundamental progress in the description of an archetypical hydrogen-bonded system: H(2)O-ice. We calculated by first principles the ice VII-VIII phase boundary, an order-disorder phase boundary, by performing a complete sampling of configurations in a 16-molecule supercell. Vibrational effects are included within quasiharmonic theory. Several important features were successfully described: negative Clapeyron slope, isotope effect, and nearly-constant T(c) at low pressures. The equation of state was very well described below 40 GPa. Inclusion of tunneling effects and increase of supercell size should decrease the remaining discrepancies, i.e., the overestimation of volume above similar to 40 GPa and the underestimation of T(c).
2010
499
4-6
236
240
http://adsabs.harvard.edu/abs/2010CPL...499..236U
https://www.sciencedirect.com/science/article/abs/pii/S0009261410013126?via%3Dihub
Umemoto, K.; Wentzcovitch, R. M.; de Gironcoli, S.; Baroni, S.
File in questo prodotto:
File Dimensione Formato  
Umemoto et al. - 2010 - Order?disorder phase boundary between ice VII and VIII obtained by first principles.pdf

non disponibili

Tipologia: Versione Editoriale (PDF)
Licenza: Non specificato
Dimensione 763.05 kB
Formato Adobe PDF
763.05 kB Adobe PDF   Visualizza/Apri   Richiedi una copia

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.11767/15008
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 38
  • ???jsp.display-item.citation.isi??? 35
social impact