<P>
Dear list,<BR>
<BR>
I would like to simulate aqueous acetone system using UA OPLS<BR>
potentials. I chose the following atoms types, given below (TABLE ONE),<BR>
for acetone, with united atom for Methyl groups.<BR>
TABLE ONE ----------------------------------------------------------------------------------<BR>
[ atoms ]<BR>
; nr type resnr resid atom cgnr charge mass<BR>
1 opls_069 1 ACET CAA 1 0.000 15.0350<BR>
2 opls_280 1 ACET C_2 1 0.470 12.0110<BR>
3 opls_069 1 ACET CAD 1 0.000 15.0350<BR>
4 opls_281 1 ACET O_2 1 -0.470 15.9994<BR>
-----------------------------------------------------------------------------------<BR>
But on the other hand, when I checked the literature, JPC<BR>
94, 1990, p.1683, I found out, the parameters are given in the following manner, TABLE TWO :<BR>
TABLE TWO<BR>
************************************************************************************<BR>
atom types charge sigma epsilon<BR>
CH3 0.062 3.910 0.160<BR>
C 0.300 3.750 0.105<BR>
O -0.424 2.960 0.210<BR>
**********************************************************************************<BR>
For keeping total charge in the system to zero, I used the opls_069 for methyl group (zero charge), in my input file, compared to what has been published. I would like to know whether the parameters (charge) I chose is right, else which atom type I must use for methyl group.<BR>
<BR>
thanking in advance,<BR>
Jes<BR>
<BR>
<BR>
<BR>
<BR>
<BR>
</P>
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