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

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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.
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==
Melting point (extract from the [[Ice Ih]] page)
:{| border="1"
|-
| <math>T_m</math> (D<sub>2</sub>0) || Pressure || [[Water models|Water model]]/technique  || Reference
|- 
|<math>257.5(5)~K</math> || 1 bar || [[Q-TIP4P/F model of water | q-TIP4P/F ]] ||  <ref name="Ramirez1"> [http://dx.doi.org/10.1063/1.3503764  R. Ramírez  and C. P. Herrero  "Quantum path integral simulation of isotope effects in the melting temperature of ice Ih", Journal of Chemical Physics 133, 144511 (2010)]</ref>
|-
| <math>276.83 \pm 0.02 K</math> || 1 bar || <FONT COLOR="#9400D3">experimental value</FONT> || <ref>[http://dx.doi.org/10.1016/j.jct.2005.09.005  N.N. Smirnova, T.A. Bykova, K. Van Durme and B. Van Mele "Thermodynamic properties of deuterium oxide in the temperature range from 6 to 350 K", The Journal of Chemical Thermodynamics '''38''' pp. 879-883 (2006)]</ref>
|}
 
:{| border="1"
|-
| <math>T_m</math> (T<sub>2</sub>0) || Pressure || [[Water models|Water model]]/technique  || Reference
|- 
|<math>259.2(5)~K</math> || 1 bar || [[Q-TIP4P/F model of water | q-TIP4P/F ]] ||  <ref name="Ramirez1"> </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]

  1. ↑ 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)
  2. ↑ Scott Habershon and David E. Manolopoulos "Free energy calculations for a flexible water model", Phys. Chem. Chem. Phys. 13 pp. 19714-19727 (2011)
  3. ↑ 3.0 3.1 3.2 R. Ramírez and C. P. Herrero "Quantum path integral simulation of isotope effects in the melting temperature of ice Ih", Journal of Chemical Physics 133, 144511 (2010)
  4. ↑ N.N. Smirnova, T.A. Bykova, K. Van Durme and B. Van Mele "Thermodynamic properties of deuterium oxide in the temperature range from 6 to 350 K", The Journal of Chemical Thermodynamics 38 pp. 879-883 (2006)
  5. ↑ H. W. Xiang "Vapor Pressure and Critical Point of Tritium Oxide", Journal of Physical and Chemical Reference Data 32 pp. 1707.1711 (2003)
  6. ↑ Carlos P. Herrero and Rafael Ramírez "Isotope effects in ice Ih: A path-integral simulation", Journal of Chemical Physics 134 094510 (2011)
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