[gmx-users] TIP5P water and Test Particle Insertion

[Joerg Sauter]

Dear Gromacs users,

I am using Test Particle Insertion with Gromacs 4.6.5. The method works 
well when I use TIP3P and SPC/E water to obtain the excess chemical 
potential of water and I get a reasonable agreement with experimental data.

However, when using TIP5P water the method diverges:

[...]
mu -1.159e+01 <mu> -1.791e+01
mu       -inf <mu>       -inf
mu -1.387e+01 <mu>       -inf
[...]

I have tried different trajectories and different ld-seed values, but 
the problem remains.
I wonder if maybe the lone-pairs might cause the problem.

Best,
Joerg