Hello,
I want to simulate a flexible water model (TIP4P/2005). I do not want use the pair style tip4p as I will add other complicated molecules like polymer in the simulation. I also do not want to use the fix rigid as I want a flexible water molecule structure.
My question is if I use the lj/charm/coul/long pair style do I need to define the M site from the water molecule data file? If so how should I proceed for that?
I have a data file for SPC/E , is there any way I can use that data file by converting it to TIP4P/2005 model ( by changing the charges, bond,angles) ?
I have used previously lj/charmm/coul/long for simulate polymer & spce water molecule before. can I use now lj/cut/tip4p/long to simulate polymer & TI4P/2005 in a similar way? I am not sure if it will have a affect on the polymer properties.
That suggests that you have been mixing force fields or using a water potential different from what the other force field parameters were parameterized for. That is generally a bad idea.
Technically speaking, yes. Whether this will give consistent results due to the differences in how the parameters were determined and how specifically the Lennard-Jones parameters are applied is outside the scope of this forum and question of general best simulation practices.
Mixing and matching different force fields or using solvents not consistent with the force field parameters used can lead to significant errors or even totally bogus results.