Q-TIP4P/F model of water: Difference between revisions

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{{stub-water}}
{{Lowercase title}}
The '''q-TIP4P/F''' model
The '''q-TIP4P/F''' model
<ref>[http://dx.doi.org/10.1063/1.3167790 Scott Habershon, Thomas E. Markland, and David E. Manolopoulos "Competing quantum effects in the dynamics of a flexible water model", Journal of Chemical Physics '''131''' 024501 (2009)]</ref>
<ref>[http://dx.doi.org/10.1063/1.3167790 Scott Habershon, Thomas E. Markland, and David E. Manolopoulos "Competing quantum effects in the dynamics of a flexible water model", Journal of Chemical Physics '''131''' 024501 (2009)]</ref>
is a flexible version of the [[TIP4P/2005]] model of [[water]] designed for use in [[Path integral formulation | path integral]] simulations. The melting point was found to be <math>251 \pm 1.5~K </math>  at 1 bar via [[Computation of phase equilibria#Direct simulation of the two phase system | direct coexistence]] calculations.
is a flexible version of the [[TIP4P/2005]] model of [[water]] designed for use in [[Path integral formulation | path integral]] simulations.  
==Melting point==
The melting point was found to be <math>251 \pm 1.5~K </math>  at 1 bar via [[Computation of phase equilibria#Direct simulation of the two phase system | direct coexistence]] calculations, and at 257K from calculations of the [[Gibbs energy function]] <ref>[http://dx.doi.org/10.1039/C1CP21520E Scott Habershon and David E. Manolopoulos  "Free energy calculations for a flexible water model", Phys. Chem. Chem. Phys. '''13''' pp. 19714-19727 (2011)]</ref>.
==Isotope effects==
==Isotope effects==
Melting point (extract from the [[Ice Ih]] page)
Melting point (extract from the [[Ice Ih]] page)
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| <math>277.64  K</math> || 0.6629 kPa || <FONT COLOR="#9400D3">experimental value</FONT> || <ref>[http://dx.doi.org/10.1063/1.1565352 H. W. Xiang "Vapor Pressure and Critical Point of Tritium Oxide", Journal of Physical and Chemical Reference Data '''32''' pp. 1707.1711 (2003)]</ref>
| <math>277.64  K</math> || 0.6629 kPa || <FONT COLOR="#9400D3">experimental value</FONT> || <ref>[http://dx.doi.org/10.1063/1.1565352 H. W. Xiang "Vapor Pressure and Critical Point of Tritium Oxide", Journal of Physical and Chemical Reference Data '''32''' pp. 1707.1711 (2003)]</ref>
|}
|}
 
It is worth pointing out that the calculations presented in the work of Ramírez and  Herrero <ref name="Ramirez1"> </ref> used the melting point of the [[Q-TIP4P/F model of water | q-TIP4P/F model]] as its "reference state". It is perhaps more fruitful to examine the relative changes upon isotopic substitution: <math>\Delta T_m (D_2O - H_2 0) = 6.5 K</math> (experimental value: 3.68 K) and <math>\Delta T_m (T_2O - H_2 0) = 8.2 K</math> (experimental value: 4.49 K).
====Ice Ih====
Isotope effects have also been studied for [[ice Ih]] <ref>[http://dx.doi.org/10.1063/1.3559466 Carlos P. Herrero and Rafael Ramírez "Isotope effects in ice Ih: A path-integral simulation", Journal of Chemical Physics '''134''' 094510 (2011)]</ref>.
==References==
==References==
<references/>
<references/>
[[category: models]]
[[category: models]]
[[category: water]]
[[category: water]]

Latest revision as of 15:49, 16 October 2017

The q-TIP4P/F model [1] is a flexible version of the TIP4P/2005 model of water designed for use in path integral simulations.

Melting point[edit]

The melting point was found to be at 1 bar via direct coexistence calculations, and at 257K from calculations of the Gibbs energy function [2].

Isotope effects[edit]

Melting point (extract from the Ice Ih page)

(D20) Pressure Water model/technique Reference
1 bar q-TIP4P/F [3]
1 bar experimental value [4]
(T20) Pressure Water model/technique Reference
1 bar q-TIP4P/F [3]
0.6629 kPa experimental value [5]

It is worth pointing out that the calculations presented in the work of Ramírez and Herrero [3] used the melting point of the q-TIP4P/F model as its "reference state". It is perhaps more fruitful to examine the relative changes upon isotopic substitution: (experimental value: 3.68 K) and (experimental value: 4.49 K).

Ice Ih[edit]

Isotope effects have also been studied for ice Ih [6].

References[edit]