[gmx-users] RE: phosphate ion force field again!

[Ing. Vojtěch Spiwok]

> Dear gmx-users,
>    Thanks for your telling me about the phosphate ion's force field.Now I
have a
>different case about phosphate ion. There is a Pi32 linear chain, and I
want to take
>the middle of this chain as an identical phosphate ion. In the Dr D. van
der Spoel's
>literature, the polyphosphate such as Pi4 and Pi8 was taken as a whole
molecule.
>In my case, I want to devide the chain into three types,every phosphate ion
in the
>polyphosphate was seen as a unit. So I need to do some regulations on the
previous
>force field! I have tried to learn the method in the literature and failed
in cracking it.
>My method was listed as follows.
>
> %chk = phosphate
> #b3lyp/6-31++g** opt SCRF(Dipole,A0=3.58,Dielectric=78.5) Pop=MK
>
> phosphate ion atomic charge
>
> -1  1
> P 0    0.283081    0.236649    0.418137
> O 0    1.531021   -0.506180   -0.280106
> O 0   -0.035156   -0.804382    1.604141
> O 0   -0.899780   -0.129669   -0.613144
> O 0    0.455368    1.658554    0.790207
> H 0    1.756866   -0.038971   -1.088440
> H 0   -0.845230   -0.531906    2.041702
>
> I do not know what the wrong is. Would you please give some advices?
Thanks a lot.
> Best wishes,
> nanyu
>
This is some Gaussian input to calculate charges or so,
maybe not exactly the topic of this list.
Could you specify details on failure ?

Vojtech Spiwok
ICT Prague