[lammps-users] Kspace_style in S P P periodic boundary condition

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1 
Hello lammps users.


I use command "kspace_style msm" for  S P P boundary conditions. 
Error happens, ERROR: Reading a data file with shrinkwrap boundaries is not compatible with a MSM KSpace style (../read_data.cpp:292) 
What kspace_style should I use? 
The commands I used are as follows:
neighbor	2.0 bin
neigh_modify	delay 0 every 1 check yes
kspace_style	msm 1.0e-4
bond_style	harmonic
angle_style	harmonic
dihedral_style	harmonic
improper_style	cvff
read_data	Nanocomposite.data
pair_style	hybrid	airebo	3.0 1 0		lj/cut/coul/msm  12.0

Can you help me with this?


Thanks.
2

Hi Yasaman,

You can use the p p p boundary. kspace is not compatible with the non-periodic boundaries.

Thanks,
Pinky

3

Thank you for your answer.

I want to pull out the graphene sheet from the polymer matrix in direction x and I can not use the periodic boundary condition.

4

a) you could use periodic boundaries, if you make your box large enough
b) as the error message states you must not use shrink-wrap boundaries with MSM, but you can use fixed boundaries.
c) MSM can handle non-periodic in any direction, but is slow and has low accuracy. with PPPM or Ewald you can use the slab correction, but then the non-periodic dimension must be z

5

Hi

Pinky,
According to the LAMMPS manual, msm style can also be used for non-periodic boundary conditions and for mixed periodic and non-periodic boundaries. Therefore, your statement is not consistent with the following part:
https://docs.lammps.org/kspace_modify.html

Yasaman,
Does “kspace_style msm” work for “f p p” boundary conditions in your simulations?

Can “kspace_modify slab” be used for your simulations?
According to the manual, the slab keyword allows an Ewald or PPPM solver to be used for systems that are periodic in x,y but non-periodic in z - a boundary setting of “boundary p p f”.

Thanks,
Hadi