Energy is not equal to zero at a distance large then Rcut

Hi,
According to the rule, if the atomic distance is greater than the Rcut, there is no interaction.
But I found that the interaction was not completely eliminated at a distance greater than Rcut
Take bilayer graphene as example: initial layer distance=3.4A, Rcut=2A, 9000 atoms

The potential function is set as follows:

pair_style hybrid/overlay lj/cut 2
pair_coeff * * none
pair_coeff 1 2 lj/cut 1.0 1.4

by " run 0 ", the interlayer energy is calculated to be ~0.5eV. Then I reduce the Rcut and the energy stays the same.
Is that normal? I think the energy should always be zero in this case

There is not enough information here to make any statement. Your choice of parameters seems odd for using metal units and it is not clear whether there are interactions due to periodic boundary conditions.
Axel

I want to verify the relationship between the interaction and the Rcut
The actual parameters are not like this
The box is large enough that the atoms occupy only part of its center

units metal
dimension 3
boundary p p p
atom_style bond
neighbor 3.0 bin

read_data 0.data

pair_style hybrid/overlay lj/cut 0.4
pair_coeff * * none
pair_coeff 1 2 lj/cut 1.0 2.5
mass 1 12.01
mass 2 12.01

timestep 0.001
neigh_modify every 5 delay 0 check yes one 10000
velocity all create 1 1233511

thermo 1
thermo_style custom time etotal
run 0

在 2019-03-04 21:23:25,“sumiya” <[email protected]…5094…> 写道:

I want to verify the relationship between the interaction and the Rcut
The actual parameters are not like this.
The box is large enough that the atoms occupy only part of its center

units metal
dimension 3
boundary p p p
atom_style bond
neighbor 3.0 bin

read_data 0.data

pair_style hybrid/overlay lj/cut 0.4
pair_coeff * * none
pair_coeff 1 2 lj/cut 1.0 2.5
mass 1 12.01
mass 2 12.01

timestep 0.001
neigh_modify every 5 delay 0 check yes one 10000
velocity all create 1 1233511

thermo 1
thermo_style custom time etotal
run 0

在 2019-03-04 21:58:05,“Axel Kohlmeyer” <[email protected]…24…> 写道:

Why should the total energy be zero, when you assign a kinetic energy?

Oh, I see. I made a stupid mistake. Thank you again