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| The '''SPC/HW''' model is an [[SPC]] model designed for heavy [[water]]. The molecule is modelled as
| | An [[SPC]] water model designed for heavy water. |
| a rigid isosceles triangle, having charges situated on each of the three atoms. Apart from Coulombic interactions, the molecules interact via long-range [[Lennard-Jones model | Lennard-Jones]] sites, situated on the oxygen atoms, i.e. (Eq. 1 in <ref>[http://dx.doi.org/10.1063/1.1359183 J. Raul Grigera "An effective pair potential for heavy water", Journal of Chemical Physics '''114''' pp. 8064-8067 (2001)]</ref>):
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| :<math>\Phi_{i,j}= \left[ \frac{C_{12}}{r_{OO}(i,j)}\right]^{12} - \left[ \frac{C_{6}}{r_{OO}(i,j)}\right]^{6} + \sum_{\alpha=1}^3 \sum_{\beta=1}^3 \frac{q_\alpha(i) q_\beta(j)}{r_{\alpha \beta}(i,j)}</math>
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| The parameters are as follows (Ref 1 Table I. Note, in the table the HOH (DOD) angle is given as 109.43 but in the text as 109.47):
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| [[Image:Thee_site_water_model.png|center|400px]]
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| {| border="1"
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| |-
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| | parameter || value
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| |-
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| | <math>C_{12}</math> || <math> 0.3428 </math> (kJ mol<sup>-1</sup>) <sup>1/12</sup>nm
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| |-
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| | <math>C_6</math> || <math> 0.3712 </math> (kJ mol<sup>-1</sup>) <sup>1/6</sup>nm
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| |-
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| | <math>r_\mathrm{OH}</math> || <math>1.000</math> Å
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| |-
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| | <math>\angle_\mathrm{HOH}</math> || <math>109.47^{\circ}</math>
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| |-
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| | <math>q_{\mathrm{O}}</math> || <math>-0.87 e</math>
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| |-
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| | <math>q_{\mathrm{H}}</math> || <math>q_{\mathrm{O}}/2</math> (charge neutrality)
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| |}
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| ==References== | | ==References== |
| <references/>
| | #[http://dx.doi.org/10.1063/1.1359183 J. Raul Grigera "An effective pair potential for heavy water", Journal of Chemical Physics '''114''' pp. 8064-8067 (2001) ] |
| ;Related reading
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| *[http://dx.doi.org/10.1021/je300064f Dibyendu Bandyopadhyay, Sadhana Mohan, Swapan K. Ghosh, and Niharendu Choudhury "Properties of Heavy Water in the Temperature Range T = 223 K to 373 K from Molecular Dynamics Simulation Using the Simple Point Charge/Heavy Water (SPC/HW) Model", Journal of Chemical and Engineering Data '''57''' pp. 1751-1758 (2012)]
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| [[category: water]] | | [[category: water]] |
| [[category: models]] | | [[category: models]] |