There are a Ni2+(H2O)6 or Ni0(H2O)2 molecule and a MOF with negative charge (proved by titration experiment, negative charge was caused by the dissociation of an OH on the MOF) in the cell.
If perform the QEq method to the whole structure, I assume that the whole Ni molecule’s charge is set to 0, so as the MOF.
Then there is little charge difference between the Ni of Ni2+(H2O)6 and Ni of Ni0(H2O)2.
Since electrostatic interaction is important for my dynamic simulation, so how can I define net charge on molecule with Qeq method?
#My input script section of QEq (The structure is set to UFF4MOF forcefield):
fix qeq1 all qeq/point 1 10 1.0e-6 200 param.qeq1
run 0
unfix qeq1
I am not entirely clear what you are asking, but if the main question is too little charge transfer between species, you might want to check the QEq parameters.
Note. Fix qeq/point enforces charge neutrality at the start of the run, but fix qeq/dynamic doesn’t, which means you can have net charge in your system with fix qeq/dynamic.
I am not entirely clear what you are asking, but if the main question is too little charge transfer between species, you might want to check the QEq parameters.
Note. Fix qeq/point enforces charge neutrality at the start of the run, but fix qeq/dynamic doesn’t, which means you can have net charge in your system with fix qeq/dynamic.
This has nothing to do with UFF – if you used fix qeq/variants then you are essentially not using the original UFF anymore. You should check your qeq parameters defined in param.qeq1. I suspect you didn’t develop these parameters?
This has nothing to do with UFF – if you used fix qeq/variants then you are essentially not using the original UFF anymore. You should check your qeq parameters defined in param.qeq1. I suspect you didn’t develop these parameters?
This has nothing to do with UFF – if you used fix qeq/variants then you are essentially not using the original UFF anymore. You should check your qeq parameters defined in param.qeq1. I suspect you didn’t develop these parameters?