Hello David A. Case,
The solvent I used is Isooctane, in pure solvent simulation the density comes to 0.7100 g/cm3 consistant with the experiment data. I used xleap command: "Solventbox RM Isooctane 20" to solvate the RM with Isooctane. In the command, "Isooctane" is just one molecule of Isooctane. Then I minimize the system and do MD with "ntr=1, restraint_wt=10.0, restraintmask=':1-448'" to restraint the RM and let the solvent equilibrate first under 300K and 1atm. The starting density of the system will be 0.4899 and the density will increase slightly and then come down to 0.4900. The density of RM and isooctane is expected to be about 0.7520. The molar ratio of solvent to RM surfactant is about 25:1. I hope these information can help to clarify my question.
What I really wonder is can I equilibrate the solvent under constant pressure with RM restraint? Thanks a lot.
Best regards,
======= At 2006-10-04, 11:06:38 you wrote: =======
>On Tue, Oct 03, 2006, Jianhui wrote:
>>
>> I solvated a reverse micelle (RM) with apolar solvent. What I do is first
>> to constrain the reverse micelle part and run MD under 300k and 1 atm to
>> equilibrate the solvent to the equilibrium density. The problem is that
>> with RM constraint here the apolar solvent didn't come down to the expected
>> density. So I wonder how the constraint actually affacted the pressure and
>> density? Is there another way that I can accomplish what I want to do?
>
>It's hard to say much without more information: how much solvent was there,
>relative to micelle? what is the solvent? do you know that you get a
>correct density in a pure solvent simulation? What kind of constraints
>(restraints?) did you use? How far off was the density? How do you know
>what the "correct" value is (i.e. with the micelle present)? And so on.
>
>...regards...dac
>
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Jianhui
tianj.rpi.edu
2006-10-04
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Received on Sun Oct 08 2006 - 06:07:08 PDT
