compute group/group

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1

Dear All,

I want to calculate “pure” electrostatic force between two groups of atoms. Can it be calculated by below command?

compute 1 group1 group/group group2 kspace yes

I read in manual "the interaction force calculated by this compute will include the force on the compute group atoms due to long-range Coulombic interactions with atoms in the specified group2. Do this command means it includes only pure electrostatic force between two groups or include both of electrostatic and VdWl force?

Thanks a lot
Yasti

2

Dear All,

I want to calculate "pure" electrostatic force between two groups of atoms.
Can it be calculated by below command?

compute 1 group1 group/group group2 kspace yes

I read in manual "the interaction force calculated by this compute will
include the force on the compute group atoms due to long-range Coulombic
interactions with atoms in the specified group2. Do this command means it
includes only pure electrostatic force between two groups or include both of
electrostatic and VdWl force?

both.

3

Thanks,

Is there any way to calculate “pure” electrostatic force between two groups?

4

Thanks,

Is there any way to calculate "pure" electrostatic force between two groups?

only after the fact, i.e. you do a trajectory and then use the rerun
command on that trajectory, but set the LJ interactions to zero.

axel.

5

The compute group/group could also be modified to only calculate the electrostatic part, replacing the "single" calculation with your calculation of interest, grabbed from the electrostatic interaction component. Alternatively, you could modify the "single" function of your pair wise interaction to only return the electrostatic part, assuming nothing else depends on it.

Brad Ewers
Texas A&M Department of Chemistry
Batteas research group