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<title>MCCCS Towhee (ClayFF)</title>
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<div align="center"> <font size="5"> <b><font face="Arial, Helvetica, sans-serif"><a name="top"></a>MCCCS
Towhee (ClayFF)</font></b> </font> </div>
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<A href="http://sourceforge.net">
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<p> </p>
<p> </p>
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<td width="697" valign="top"> <b>Overview</b>
<ul>
This section covers the ClayFF force field as it is implemented into
the towhee_ff_ClayFF file in the ForceFields directory. All of the Towhee atom types for the ClayFF force
field are listed, along with a short description of their meanings.
Any discrepencies (especially typos) from the published force field values are the sole responsibility
of Marcus G. Martin, and I welcome feedback on how this implementation compares
with other programs.
<p> </p>
</ul>
<b>References for ClayFF</b>
<ul>
There is currently one source for ClayFF.
<ul>
<li><a href="../references.html#cygan_et_al_2004">Cygan <i>et
al.</i> 2004</a></li>
</ul>
</ul>
<b>ClayFF in Towhee</b>
<ul>
The official force field name for these parameters is 'ClayFF'. Here I list all of the ClayFF
atom names for use in the towhee_input file, along with a brief
description. Please note that the capitalization and spacing pattern is important
and must be followed exactly as listed here.
<ul>
<li><b>'h*'</b> : water hydrogen</li>
<li><b>'ho'</b> : hydroxyl hydrogen</li>
<li><b>'o*'</b> : water oxygen</li>
<li><b>'oh'</b> : hydroxyl oxygen</li>
<li><b>'ob'</b> : bridging oxygen</li>
<li><b>'obos'</b> : bridging oxygen with octahedral substitution</li>
<li><b>'obts'</b> : bridging oxygen with tetrahedral substitution</li>
<li><b>'obss'</b> : bridging oxygen with double substitution</li>
<li><b>'ohs'</b> : hydroxyl oxygen with substitution</li>
<li><b>'st'</b> : tetrahedral silicon</li>
<li><b>'ao'</b> : octahedral aluminum</li>
<li><b>'at'</b> : tetrahedral aluminum</li>
<li><b>'mgo'</b> : octahedral magnesium</li>
<li><b>'mgh'</b> : hydroxide magnesium</li>
<li><b>'cao'</b> : octahedral calcium</li>
<li><b>'cah'</b> : hydroxide calcium</li>
<li><b>'feo'</b> : octahedral iron</li>
<li><b>'lio'</b> : octahedral lithium</li>
<li><b>'Na'</b> : aqueous sodium ion</li>
<li><b>'K'</b> : aqueous potassium ion</li>
<li><b>'Cs'</b> : aqueous cesium ion</li>
<li><b>'Ca'</b> : aqueous calcium ion</li>
<li><b>'Ba'</b> : aqueous barium ion</li>
<li><b>'Cl'</b> : aqueous chloride ion</li>
</ul>
</ul>
<b>Coulombic Interactions</b>
<ul>
This force field uses point charges on atomic centers. Here we list suggested charges for each of the
atom types in this force field.
<ul>
<li><b>'h*'</b> : 0.4100</li>
<li><b>'ho'</b> : 0.4250</li>
<li><b>'o*'</b> : -0.8200 </li>
<li><b>'oh'</b> : -0.9500 </li>
<li><b>'ob'</b> : -1.0500 </li>
<li><b>'obos'</b> : -1.1808</li>
<li><b>'obts'</b> : -1.1688</li>
<li><b>'obss'</b> : -1.2996</li>
<li><b>'ohs'</b> : -1.0808 </li>
<li><b>'st'</b> : 2.1000 </li>
<li><b>'ao'</b> : 1.5750 </li>
<li><b>'at'</b> : 1.5750 </li>
<li><b>'mgo'</b> : 1.3600</li>
<li><b>'mgh'</b> : 1.0500</li>
<li><b>'cao'</b> : 1.3600</li>
<li><b>'cah'</b> : 1.0500</li>
<li><b>'feo'</b> : 1.5750</li>
<li><b>'lio'</b> : 0.5250</li>
<li><b>'Na'</b> : 1.0 </li>
<li><b>'K'</b> : 1.0 </li>
<li><b>'Cs'</b> : 1.0</li>
<li><b>'Ca'</b> : 2.0</li>
<li><b>'Ba'</b> : 2.0</li>
<li><b>'Cl'</b> : -1.0</li>
</ul>
</ul>
<b>Improper torsions</b>
<ul>
There are no improper torsions in this force field.
</ul>
<b>Proteins</b>
<ul>
This forcefield is not designed for proteins.
</ul>
<a href="../towhee_capabilities.html">Return to the Towhee Capabilities web page</a>
<p> </p>
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<i><font size="2">Send comments to:</font></i> <font size="2">
<a href="mailto:marcus_martin@users.sourceforge.net">Marcus G. Martin</a><br>
<i>Last updated:</i>
<!-- #BeginDate format:Am1 -->September 07, 2005<!-- #EndDate -->
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