[lammps-users] (no subject)

Hi ,
i am trying to simulate some CO2 molecules in a simple box. the code i have used is the following:

dimension 3
boundary p p p
units real
neighbor 2.0 bin
neigh_modify delay 0.5
atom_style full
bond_style harmonic
angle_style harmonic
pair_style lj/cut/coul/cut 8 10
pair_modify mix arithmetic

read_data CO2data.data

velocity all create 300 8745350 loop geom

pair_coeff 1 1 4.5512 3.014 4.5512 3.014 #OO epsilon(kcal/mol) sigma(A)
pair_coeff 1 2 2.6892 2.8995 2.6892 2.8995 #OC Lorentz-Berthelot
pair_coeff 2 2 1.5890 2.785 1.5890 2.785 #CC

bond_coeff 1 5000 1.16
angle_coeff 1 4500 180.0

fix 1 all shake 1e-6 800 1000 a 1

compute 1 all temp
#equilibrate

thermo 300
thermo_style multi
timestep 0.5
run 20000 #100ps equilibration
write_restart co2box_30x30data.equil.restart

#production run

thermo 500
log produc.log
thermo_style custom etotal ke temp pe ebond eangle edihed eimp evdwl ecoul elong press vol pxx pyy pzz pxy pxz pyz
thermo_modify line multi

timestep 1.0
dump 2 all atom 5000 co2box30x30.01_298K.dump
dump_modify 2 image yes scale yes
dump 3 all atom 100 co2.xyz

fix 3 all rdf 500 rdf.out 500 1 1 1 2 2 2

run 25000
write_restart co2box30.restart

among other problems that i face and i hope i will sometime..., i see at the output that the bond and angle energy are all the time set to zero.why is this happening?

Thanks
Dimitris

among other problems that i face and i hope i will sometime..., i see at the output that the bond and angle >energy are all the time set to zero.why is this happening?

Well, you don't appear to have a time-integration fix, like fix nve defined,
so your atoms won't move. LAMMPS should have printed a warning about
this. Also, if using shake, then the bonds and angles will be frozen
at their equilibrium position, which means their energy is (near) 0.0.

Steve