Hi
I am relaxing a carbon nanospring using the AIREBO potential. Spring structure is created using the Chuang et al. procedure [J. Chem. Inf. Model. 2009, 361-368].
I tried with (i) only MD runs and (ii) CG+MD. During the MD runs spring structure collapses (blows out) while during the CG minimization it does not.
I tried with different ensemble (NVE, NVT), different range of time step, temp. Nothing works.
I am using lasted lammps version. Here is input script and input data file for the spring.
This input script works for CNT relaxation.
Since during the CG minimization spring structure does not collapse, I am guessing initial structure is ok.
I will appreciate your comments/suggestions on this problem.
Kind regards,
Sanjib
************** INPUT SCRIPT *******************
Variables
variable input index spring-pitch25-3uc-data.txt
INITIALIZATION
units metal
boundary p p p
atom_style atomic
processors 3 4 1
ATOM DEFINITION
read_data ${input}
FORCE FIELD
pair_style airebo 3.0 0 0
pair_style rebo
pair_coeff * * CH.airebo C
SETTINGS
neighbor 3.0 bin
neigh_modify delay 1
------------------------------ RELAXATION -----------------------------------
thermo_style custom step cpu temp pe vol
variable peng equal pe
variable istep equal step
thermo 1000
output for VMD
dump 1 all custom 10000 dump.torus id type xs ys zs
fix 10 all print 1000 “{istep}, {peng}” file energy-data.txt screen no
min_style cg
minimize 1e-25 1e-25 10000 10000
fix 1 all nve
#fix 2 all nvt temp 1.0 1.0 100.0
timestep 0.00005
run 100000
************** INPUT DATA FOR NANOSPRING *******************
864 atoms
1 atom types
-50.00 50.00 xlo xhi
-50.00 50.00 ylo yhi
-50.00 50.00 zlo zhi
Masses
1 12.080000
Atoms
1 1 0.0000 4.3220 4.5850
2 1 0.0000 4.3220 3.1450
3 1 -1.2500 4.3220 2.7310
.
.
.
.
859 1 4.9900 2.8810 18.5280
860 1 6.2350 0.7250 18.0860
861 1 3.7420 3.6040 18.7920
862 1 4.9920 1.4380 18.2640
863 1 3.1180 3.2440 18.1140
864 1 4.3680 1.0780 17.5030