[gmx-users] Widom Test Particle insertion method

[dimitris.g.mintis]

Dear gromacs users,

 

I am facing a problem when I try to calculate the excess chem potential of
TIP3P (at 300K from a long MD trajectory of 50ns in the nPT ensemble), since
I get the <mu> to be around 2.3x10-4 kJ/mol and the mu to be around
9.193e+00 whereas the experimental value for water is around -26 kJ/mol. 

 

I have added one extra molecule of water H20, all three atoms located at
0.0.0, in the *.gro file and I kept the radius rtpi at 0.05. Any help will
be really really appreciated !!! 

 

Thanks in advance (I use gromacs 4.6 version)

Dimitris