[gmx-users] TIP5P - dummies sit on top of each other

David van der Spoel spoel at xray.bmc.uu.se
Tue May 12 15:34:36 CEST 2009


ilona.baldus at bioquant.uni-heidelberg.de wrote:
> 
> Hi,
> 
> I am trying to change my ice crystal from a three-site water model to 
> the TIP5P water model. For that I use pdb2gmx. The program adds the two 
> dummy atoms, but they are at exactly the same position as the oxygen and 
> not two additional sites as stated by the paper and also as I find in 
> the file /gromacs/top/tip5p.gro.
> 
Check again after 1 step of MD.

> For a small ice crystal my problem looks like this:
> 
> Original ice.gro file:
> 
> Groningen Machine for Chemical Simulation
>    24
>     2 SOL    OW    1   0.000   0.000   0.000
>     2 SOL   HW1    2   0.000   0.000   0.096
>     2 SOL   HW2    3   0.078   0.045  -0.032
>     3 SOL    OW    4   0.224   0.129  -0.091
>     3 SOL   HW1    5   0.224   0.129  -0.187
>     3 SOL   HW2    6   0.302   0.084  -0.059
>     4 SOL    OW    7   0.224   0.387   0.000
>     4 SOL   HW1    8   0.146   0.433  -0.032
>     4 SOL   HW2    9   0.224   0.297  -0.032
>     5 SOL    OW   10   0.000   0.517  -0.091
>     5 SOL   HW1   11  -0.078   0.472  -0.059
>     5 SOL   HW2   12   0.000   0.607  -0.059
>     6 SOL    OW   13   0.000   0.000   0.274
>     6 SOL   HW1   14  -0.078   0.045   0.306
>     6 SOL   HW2   15   0.000  -0.090   0.306
>     7 SOL    OW   16   0.224   0.129   0.365
>     7 SOL   HW1   17   0.146   0.084   0.333
>     7 SOL   HW2   18   0.224   0.219   0.333
>     8 SOL    OW   19   0.224   0.387   0.274
>     8 SOL   HW1   20   0.224   0.387   0.178
>     8 SOL   HW2   21   0.302   0.433   0.306
>     9 SOL    OW   22   0.000   0.517   0.365
>     9 SOL   HW1   23   0.000   0.517   0.461
>     9 SOL   HW2   24   0.078   0.472   0.333
>    0.44744   0.77499   0.73067
> 
> 
> Modified (supposedly tip5p) .gro file:
> 
> Groningen Machine for Chemical Simulation
>    40
>     1HO5    HW1    1   0.000   0.000   0.096
>     1HO5    HW2    2   0.078   0.045  -0.032
>     1HO5     OW    3   0.000   0.000   0.000
>     1HO5    HW3    4   0.000   0.000   0.000
>     1HO5    HW4    5   0.000   0.000   0.000
>     2HO5    HW1    6   0.224   0.129  -0.187
>     2HO5    HW2    7   0.302   0.084  -0.059
>     2HO5     OW    8   0.224   0.129  -0.091
>     2HO5    HW3    9   0.224   0.129  -0.091
>     2HO5    HW4   10   0.224   0.129  -0.091
>     3HO5    HW1   11   0.146   0.433  -0.032
>     3HO5    HW2   12   0.224   0.297  -0.032
>     3HO5     OW   13   0.224   0.387   0.000
>     3HO5    HW3   14   0.224   0.387   0.000
>     3HO5    HW4   15   0.224   0.387   0.000
>     4HO5    HW1   16  -0.078   0.472  -0.059
>     4HO5    HW2   17   0.000   0.607  -0.059
>     4HO5     OW   18   0.000   0.517  -0.091
>     4HO5    HW3   19   0.000   0.517  -0.091
>     4HO5    HW4   20   0.000   0.517  -0.091
>     5HO5    HW1   21  -0.078   0.045   0.306
>     5HO5    HW2   22   0.000  -0.090   0.306
>     5HO5     OW   23   0.000   0.000   0.274
>     5HO5    HW3   24   0.000   0.000   0.274
>     5HO5    HW4   25   0.000   0.000   0.274
>     6HO5    HW1   26   0.146   0.084   0.333
>     6HO5    HW2   27   0.224   0.219   0.333
>     6HO5     OW   28   0.224   0.129   0.365
>     6HO5    HW3   29   0.224   0.129   0.365
>     6HO5    HW4   30   0.224   0.129   0.365
>     7HO5    HW1   31   0.224   0.387   0.178
>     7HO5    HW2   32   0.302   0.433   0.306
>     7HO5     OW   33   0.224   0.387   0.274
>     7HO5    HW3   34   0.224   0.387   0.274
>     7HO5    HW4   35   0.224   0.387   0.274
>     8HO5    HW1   36   0.000   0.517   0.461
>     8HO5    HW2   37   0.078   0.472   0.333
>     8HO5     OW   38   0.000   0.517   0.365
>     8HO5    HW3   39   0.000   0.517   0.365
>     8HO5    HW4   40   0.000   0.517   0.365
>    0.44744   0.77499   0.73067
> 
> Is that a known error? What can I do
> 
> Best wishes,
> 
> Ilona
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-- 
David van der Spoel, Ph.D., Professor of Biology
Molec. Biophys. group, Dept. of Cell & Molec. Biol., Uppsala University.
Box 596, 75124 Uppsala, Sweden. Phone:	+46184714205. Fax: +4618511755.
spoel at xray.bmc.uu.se	spoel at gromacs.org   http://folding.bmc.uu.se



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