<html>
<head>
<title>MCCCS Towhee (TIP5P)</title>
</head>
<body bgcolor="#FFFFFF" text="#000000">
<table width="675" border="0" cellspacing="0" cellpadding="0" height="590">
<tr>
<td colspan="2" height="29">
<div align="center"> <font size="5"> <b><font face="Arial, Helvetica, sans-serif"><a name="top"></a>MCCCS
Towhee (TIP5P)</font></b> </font> </div>
</td>
</tr>
<A href="http://sourceforge.net">
<IMG src="http://sourceforge.net/sflogo.php?group_id=87039&type=5" width="210" height="62" border="0"
alt="SourceForge.net Logo" align="right"/>
</A>
<tr>
<td width="18" height="371" valign="top">
<p> </p>
<p> </p>
</td>
<td width="697" valign="top"> <b>Overview</b>
<ul>
This section covers the TIP5P force field for water as it is implemented into the towhee_ff_TIP5P file in the
ForceFields directory. All of the Towhee atom types for this force field
are listed, along with a short description of their meanings. TIP5P is a rigid
water model that has a Lennard-Jones site on the Oxygen and bare charge sites on the Hydrogens and on the
lone electron pairs.
TIP5P is a branched, rigid molecule (when you consider the lone pairs) and therefore configurational-bias
is currently unable to generate structures so you will need to provide an initial structure and also use the rotational-bias
moves instead of the configurational-bias moves for molecule transfers between simulation boxes.
The Jorgensen group has also parameterized two other water models that utilize different numbers of interaction sites.
Please see the <a href="tip3p.html">TIP3P</a>and <a href="tip4p.html">TIP4P</a> web pages for more information
about those water models. This water model is suitable for use with any Lennard-Jones forcefield, but is
especially well suited for the OPLS family of potentials. Please see the <a href="oplsua.html">OPLS-ua</a>,
<a href="oplsaa.html">OPLS-aa</a>, and <a href="opls2001.html">OPLS-2001</a> web pages for more information.
Any discrepencies (especially typos) from the published force field values are the sole responsibility of
<a href="mailto:marcus_martin@users.sourceforge.net">Marcus Martin</a>, and I welcome feedback on how this
implementation compares with other programs.
<p> </p>
</ul>
<b>References for TIP5P</b>
<ul>
TIP5P was originally published in the following paper
<ul>
<li><a href="../references.html#mahoney_jorgensen_2000">Mahoney and Jorgensen 2000</a></li>
</ul>
</ul>
<b>TIP5P in Towhee</b>
<ul>
The official force field name for TIP5P in Towhee is 'TIP5P'. Here
I list all of the atom names for use in the towhee_input file,
along with a brief description taken from the literature.
Please note that the capitalization and spacing pattern is important and must be
followed exactly as listed here.
<ul>
<li><b>'H'</b> : hydrogen in water</li>
<li><b>'O'</b> : oxygen in water</li>
<li><b>'L'</b> : charge site on lone pair positions in an sp<sup>3</sup> hybridization
of oxygen</li>
</ul>
</ul>
<b>Coulombic interactions</b>
<ul>
TIP5P uses atom-centered point charges to represent the electrostatic interactions.
Here are the suggested charge assignments for water.
<ul>
<li><b>'H'</b>: 0.241</li>
<li><b>'O'</b>: 0.0</li>
<li><b>'L'</b>: -0.241</li>
</ul>
</ul>
<b>Improper torsions</b>
<ul>
There are no improper torsions for this force field.
</ul>
<a href="../towhee_capabilities.html">Return to the Towhee Capabilities web page</a>
<p> </p>
</td>
</tr>
</table>
<hr width="715" align="left">
<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 -->
</font> <br>
</body>
</html>
