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# Lammps System Dipole

As part of my research in Philadelphia with Matt, we needed to calculate system
dipoles using LAMMPS. We were having a lot of trouble using the provided
`dipole/chunk`

compute so we went about figuring it out another way instead.
This was a pain to do (could not find it anywhere on the internet, probably
because everyone else is smart enough to figure out how to use `dipole/chunk`

)
so here is how we ended up doing it:

```
variable dipole_x atom x*q
variable dipole_y atom y*q
variable dipole_z atom z*q
#systemDipole_x
compute sD_x all reduce sum v_dipole_x
compute sD_y all reduce sum v_dipole_y
compute sD_z all reduce sum v_dipole_z
#just in case you need only one dipole...
#variable system_dipole_x equal c_sD_x
variable total_system_dipole equal sqrt((c_sD_x*c_sD_x)+(c_sD_y*c_sD_y)+(c_sD_z*c_sD_z))
fix get_total_system_dipole all print 1 "$(step) ${total_system_dipole}" file "dipole.txt"
```

132 Words

2018-07-10 11:23

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