Dear Roitberg and Jason
Thank you for point out my mistake.
Yes it is 99.5% choline lactate and 0.5% water in this system. And I am
running with different percentage of IL.
For 100% choline lactate system
------------------------------------------------------------------------------
A V E R A G E S O V E R 2500000 S T E P S
NSTEP = 2500000 TIME(PS) = 35590.000 TEMP(K) = 297.96 PRESS =
1.0
Etot = 1807.4839 EKtot = 13944.1153 EPtot =
-12136.6315
BOND = 5148.9220 ANGLE = 8238.6012 DIHED =
4052.6302
1-4 NB = 2770.0536 1-4 EEL = 5548.6008 VDWAALS =
-8363.3905
EELEC = -29532.0487 EHBOND = 0.0000 RESTRAINT =
0.0000
EKCMT = 960.4335 VIRIAL = 957.3126 VOLUME =
146678.9676
Density =
1.1201
Ewald error estimate: 0.2555E-02
------------------------------------------------------------------------------
For 99.5% choline lactate and 0.5% water system
------------------------------------------------------------------------------
A V E R A G E S O V E R 2500000 S T E P S
NSTEP = 2500000 TIME(PS) = 30590.000 TEMP(K) = 297.95 PRESS =
1.0
Etot = 1366.4317 EKtot = 13993.8146 EPtot =
-12627.3829
BOND = 5142.8490 ANGLE = 8228.4576 DIHED =
4045.2279
1-4 NB = 2770.8857 1-4 EEL = 5725.9239 VDWAALS =
-8217.3621
EELEC = -30323.3648 EHBOND = 0.0000 RESTRAINT =
0.0000
EKCMT = 987.0209 VIRIAL = 983.7836 VOLUME =
147776.7168
Density =
1.1175
Ewald error estimate: 0.2444E-02
------------------------------------------------------------------------------
For 99% choline lactate and 1.0% water system
------------------------------------------------------------------------------
A V E R A G E S O V E R 2500000 S T E P S
NSTEP = 2500000 TIME(PS) = 35590.000 TEMP(K) = 297.95 PRESS =
1.0
Etot = 905.6418 EKtot = 14041.7827 EPtot =
-13136.1409
BOND = 5138.6650 ANGLE = 8233.4022 DIHED =
4043.5382
1-4 NB = 2769.8187 1-4 EEL = 5744.7354 VDWAALS =
-8111.2161
EELEC = -30955.0842 EHBOND = 0.0000 RESTRAINT =
0.0000
EKCMT = 1012.0545 VIRIAL = 1008.8662 VOLUME =
148219.8584
Density =
1.1196
Ewald error estimate: 0.2371E-02
------------------------------------------------------------------------------
Please suggest me
Thank you in advanced
Rahman
'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
*Md Homaidur Rahman*
PhD Research Scholar
Computational Biophysics Lab.
Department of Biotechnology
Indian Institute of Technology-Madras
Chennai-600 036
*Mobile No = +91- 7845991785*
'''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
On Tue, Dec 30, 2014 at 4:53 AM, Jason Swails <jason.swails.gmail.com>
wrote:
> On Mon, Dec 29, 2014 at 5:29 PM, Adrian Roitberg <roitberg.ufl.edu> wrote:
>
> > I slightly disagree with Jason here.
> >
> > 0.5% Choline Lactate solution in water, is mostly water, right? There is
> > no way that has a positive energy.
> >
> > If by 0.5% choline lactate you mean 99.5% choline lactate, 0.5% water,
> > then it might be a different story. In any case, an ionic liquid energy
> > would be cominated by electrostatic attraction between molecules of
> > opposite charge, so I would also expect negative energies all around.
> >
>
> But what's the minimum energy of a single Choline molecule? It is quite
> possibly positive, in which case adding a lot of them could result in a
> very positive energy (if attractive intermolecular forces cannot fully
> "offset" the positive energy of the choline molecule itself). But this
> doesn't indicate a problem in itself -- only energy differences hold any
> meaning in molecular mechanical simulations.
>
> However, bulk water has a very strongly negative overall energy, so I would
> agree that a 99.5% water -- 0.5% choline mixture should be negative, and a
> positive energy would indicate a problematic system (perhaps it is overly
> compressed). I admit to reading the OP as 99.5% choline lactate + 0.5%
> water, then 99% choline lactate and 1% water (this would make sense given
> the trend of decreasing total energies).
>
> If the system is mostly water, the energy should be negative and you should
> look for a problem. If it is mostly choline lactate, then it could very
> well be mostly positive.
>
> At the end of the day, a positive energy does not, by itself, indicate any
> kind of problem (nor does a negative energy mean that there are no
> problems).
>
> HTH,
> Jason
>
> --
> Jason M. Swails
> BioMaPS,
> Rutgers University
> Postdoctoral Researcher
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Received on Mon Dec 29 2014 - 22:00:02 PST
