Dear lammps users
I want to increase CNT temperature from 300 K to 3000 K using fix nvt to indicate deformation of CNT during rising temperature, but by using different values for run steps (1e6 - 5e6) temperature increases from 284 K to 2400 K (not 3000 K) and the fluctuation of temperature becomes worse in last steps.
What is the problem in my code?
Input file:
units metal
dimension 3
atom_style atomic
boundary s s s
timestep 1e-3
thermo 5000
---------- Simulation Box -----------------------------
read_data data4rows_CC.DAT
---------- Define Interatomic Potential --------------
pair_style airebo 3.0 1 1
pair_coeff * * CH.airebo C C C
---------- Define Settings ----------------------------
neighbor 2.0 bin
group 1 type 1
group 2 type 2
group 3 type 3
group 4 union 3 2
variable energy equal pe
velocity all create 300 511124 rot yes mom yes
fix relax all nvt temp 300 300 .01
run 5000
unfix relax
thermo_style custom fmax fnorm
min_style cg
minimize 0 0 1000 1000000
fix 1 all ave/time 10 1000 5000 v_energy file energy.ENERGY
dump Dump all atom 5000 dump.atom
fix BCS1 2 setforce 0 0 0
fix BCS2 3 setforce 0 0 0
fix 2 1 nvt temp 300 3000 0.01
thermo_style custom step temp vol pe
run 5000000
Log file:
Step Temp Volume PotEng
5206 284.31927 2631.14 -3030.4308
10000 296.34888 2631.14 -3016.4387
15000 316.58998 2631.14 -3016.9915
20000 313.8892 2631.14 -3017.2473
25000 308.7575 2631.14 -3016.3638
30000 304.42983 2631.14 -3016.3574
35000 300.93349 2631.14 -3016.269
40000 327.6437 2631.14 -3016.3581
45000 333.01652 2631.14 -3016.3849
.
.
.
4955000 2609.2883 2969.9359 -2886.6763
4960000 2516.4965 3111.203 -2903.0597
4965000 2384.5191 3060.6625 -2884.6268
4970000 2563.0181 2962.0201 -2893.2835
4975000 2246.5307 2964.8463 -2886.581
4980000 2631.0518 3032.7612 -2890.2143
4985000 2538.1501 2951.2105 -2899.0179
4990000 2557.3639 3254.5606 -2902.3723
4995000 2455.0836 2920.3391 -2882.1587
5000000 2460.8735 2983.119 -2881.0655
5005000 2431.1345 3293.5626 -2890.205
5005206 2417.2462 3025.1247 -2889.2442
Thanks