[lammps-users] Problem about "kspace_modify slab"

Hi, lammpsusers

I want to simulate a 2d period system. So I used "kspace_style pppm
1e-4" and "kspace_modify slab 3.0". The log shows there are atoms out
of range, cannot compute pppm. I am sure the initial position of every
atom is inside the box. However, there are velocity section in the
data.file.

Here is part of my in.script:

# Created by charmm2lammps v1.8.1 on Sun Apr 4 20:05:41 CST 2010
boundary p p f
#neighbor 10.0 bin
units real
neigh_modify delay 2 every 1

atom_style full
bond_style harmonic
angle_style charmm
dihedral_style charmm
improper_style harmonic

pair_style lj/charmm/coul/long 8 10
pair_modify mix arithmetic
kspace_style pppm 1e-4
kspace_modify slab 3.0

read_data data.test

special_bonds charmm

.....

Di Cheng

University of Science and Technology of China
Hefei, Anhui Province 230026
P. R. China
E-mail: [email protected]...
Tel.: +86-15321055911

Do you have anything keeping the atoms from leaving the non-periodic direction? A wall or group of rigid atoms?
Matt

Quoting ?? <[email protected]...>:

Hi, Matt K. Peterson

I've added a wall/reflect zlo zhi

Di Cheng

University of Science and Technology of China
Hefei, Anhui Province 230026
P. R. China
E-mail: [email protected]...
Tel.: +86-15321055911

I've had problems with wall/reflect and energy conservation. I think it's better to have an LJ wall, or some other potential.
Matt

Quoting 程迪 <[email protected]...>:

Do you get the error immediately (timestep 0),
or after you run a while. In the latter case, you
are probably moving the atoms too far, too fast,
e.g. not reneighboring often enough, or blowing
atoms out of the box.

Steve