Editing SPC/HW model of water
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The '''SPC/HW''' model is an [[SPC]] model designed for heavy [[water]]. The molecule is modelled as | The '''SPC/HW''' model is an [[SPC]] model designed for heavy [[water]]. The molecule is modelled as | ||
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. ( | 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. (Ref. 1 Eq. 1): | ||
:<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> | :<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> | ||
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): | 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): | ||
[[Image: | [[Image:Water_empirical1.png|center|300px]] | ||
{| border="1" | {| border="1" | ||
|- | |- | ||
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| <math>C_6</math> || <math> 0.3712 </math> (kJ mol<sup>-1</sup>) <sup>1/6</sup>nm | | <math>C_6</math> || <math> 0.3712 </math> (kJ mol<sup>-1</sup>) <sup>1/6</sup>nm | ||
|- | |- | ||
| <math>r_\mathrm{OH}</math> || <math>1.000</math> | | <math>r_\mathrm{OH}</math> || <math>1.000\mathrm{\AA}</math> | ||
|- | |- | ||
| <math>\angle_\mathrm{HOH}</math> || <math>109.47^{\circ}</math> | | <math>\angle_\mathrm{HOH}</math> || <math>109.47^{\circ}</math> | ||
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|- | |- | ||
| <math>q_{\mathrm{H}}</math> || <math>q_{\mathrm{O}}/2</math> (charge neutrality) | | <math>q_{\mathrm{H}}</math> || <math>q_{\mathrm{O}}/2</math> (charge neutrality) | ||
|- | |||
| <math>r_\mathrm{OM}</math> || <math>0</math> (charge sits on oxygen) | |||
|} | |} | ||
==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) ] | |||
[[category: water]] | [[category: water]] | ||
[[category: models]] | [[category: models]] |