Hi Shijie,
Though I haven’t tried myself, I suspect that it will be very difficult to converge water/methanol mixtures with all-atom models.
I suggest using a united atom model for methanol. Adjust the LJ parameters on the united atom methyl group until you get reasonable results for pure methanol. What is reasonable depends on what you are interested in. It could be compressibility or the radial distribution function, for example. Try mixtures after you have this working.
For strategies for difficulty to converge models, see the end of section 7.4.1 in the manual.
Also note that the default units for density are M. You have a very low density in your input file.
Hope this helps,
Tyler
> On Jul 11, 2016, at 7:30 PM, Shijie Sheng <sshen004.ucr.edu> wrote:
>
> Hi,
>
> I am having a hard time making rism1d converge for a methanol/water
> mixture solvent at room temperature.
> The mdl files of water and methanol are from the existing folder
> under $AMBERHOME/dat/rism1d/model. The parameter input file is shown below.
>
>
> &PARAMETERS
> OUTLST='GU', THEORY='DRISM', CLOSUR='KH',
> !grid
> NR=16384, DR=0.025, routup=384, toutup=0,
> !MDIIS
> NIS=20, DELVV=0.3, TOLVV=1.e-12,
> !iter
> KSAVE=-1, KSHOW=1, maxste=10000,
> !ElStat
> SMEAR=1, ADBCOR=0.5,
> !bulk solvent properties
> TEMPER=298, DIEps=46.81,
> NSP=2
> /
> &SPECIES
> DENSITY=0.1719d0,
> MODEL="$AMBERHOME/dat/rism1d/model/SPC.mdl"
> /
> &SPECIES
> DENSITY=0.1719d0,
> MODEL="$AMBERHOME/dat/rism1d/model/MOH.mdl"
> /
>
> I really appreciate your time. Thank you.
>
>
> --
> Best regards,
> ------------------------
> Shijie Sheng
> UCR CEE Department
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Received on Mon Jul 11 2016 - 19:30:02 PDT
