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David,<br><br>
<blockquote type=cite class=cite cite>>
DHvap = 43.21
versus 58.0<br>
You're saying that it is 14.7 kJ/mole off? Hmm, what molecule is
this?</blockquote><br>
Yes, that is what I have gotten from the liquid and gas
calculations. Propylene glycol or 1,2-propanediol. <br><br>
(I have searched around looking for those that have simulated it
previously, and I get the feeling someone should have, but I can't find
any references.)<br><br>
<blockquote type=cite class=cite cite>What you may need to do is to
increase the dipole (like e.g. spc water<br>
has 2.25 iso 1.85) to account for polarisation. You can actually<br>
optimize the parameters during an MD simulation by coupling the<br>
parameters to the energy and the pressure. Since there are two<br>
observables you have two degrees of freedom, i.e. you can scale the<br>
charges to account for higher DHvap, and one of the C12 parameters
to<br>
get the pressure right. See e.g. JCP 108 pp. 10220-10230 (1998) and
<br>
JPC B. 105 pp. 2618-2626 (2001) (pdfs available from my website
below)</blockquote><br>
Thank you for the references. They have been a great
help.<br><br>
Is the parameter coupling an active feature of the current release of
GROMACS? Been through the manual a couple of times, searched the
site etc. and haven't been able to find any mention of it.<br><br>
Catch ya,<br>
<x-sigsep><p></x-sigsep>
<b>Dr. Dallas Warren<br>
</b><i>Research Fellow<br>
</i>Department of Pharmaceutical Biology and Pharmacology<br>
Victorian College of Pharmacy, Monash University<br>
381 Royal Parade, Parkville VIC 3010<br>
<font color="#0000FF"><u>dallas.warren@vcp.monash.edu.au<br>
</u></font>+61 3 9903 9083<br>
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