[gmx-users] Re: nve ensemble

[Erik Lindahl]

Ah,

That sounds like a nice way of saying "we don't know, but everybody 
else was doing that, so we did it too" :-)

There is nothing *wrong* with NVE (or NVT), but as other people here 
have already pointed out: any difference between ensembles is going to 
be insignificant compares to the errors due to potentials not being 
designed for high-temperature simulations...

Allen & Tildesley doesn't cover high-temperature simulations 
specifically as far as I recall, but it's still a highly recommended 
book - you can probably find it on Amazon.

Cheers,

Erik



On May 4, 2004, at 10:46 PM, Linda wrote:

> Yes, XAvier, I asked them why use nve ensemble at high temperature? 
> their answer is "this is very basic MD simulation question". While I 
> do have no idea about it, so I ask it in mailinglist.
>
> While a book named "Computer Simulation in chemical physics" edited by 
> Allen and Tildesley may address this question. Unfortunately, our lib 
> does not have this book. I hope you can find it out and share it with 
> all.
>
> 	In fact, I searched PUBMED by key word "high temperature, nvt", but I 
> found 0 paper, so I want to know if you have such paper.
>
> 	As for pressure, you can read their paper. I remember the pressure is 
> aournd 0.25 at 498K simulation, but not quite sure.
>
> 	By the way, I wonder if it is slow to run REMD?
>
> Luck,
>
> Linda
>
>> Hi, XAvier,
>>
>> 	I am sure they use NVE ensemble. You can refer paper "JMB, 2002, 
>> 322: 189-203". I asked their author about it, their answer is NVE 
>> ensemble. In fact, there are a bundle of papers which uses NVE 
>> ensemble at high-temperature. While, the water density at high-T is 
>> different from that at low-T.
>>
>>
> That's right they use NVE. Dis you ask them why they chose this 
> ensemble
> ? That is not
> a bad choice anyway, since they actually fix the volume to the 
> reproduce
> the experimental
> density of their solvent. I don't know if they mention anything about
> the pressure inthe paper.
>
>> 	Can you post some representative papers which is related to 
>> high-temperature NVT MD simulation? So that I can compare them.
>>
>>
> Actually no. But I've red several paper using the replica exchange
> methodology
> (Garcia, Pande for exemple) and most of them run their simulations in
> NVT. I run
> some of them also at NVT.
>
> Perhaps somebody has the aswers ??? Why NVE rather than NVT ???
>
> XAvier
>
>
>
>
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