Dear all,
I used lammps-airebo potential for a short NVE test for (8,4) carbon
nanotubes at the relaxed status (bondlength = 1.42A).
The output of lammps indicates total Energy = -822 Kcal/mol (112
atoms total) equivalent to -0.32 eV/atom. It does not make sense to
me, since using the potential equations in Brenner's paper, even just
two body potential will give me -6 eV/atom (full potential
-7.2eV/atom for my CNT). The lammps output temperature ~ 0.3K also
looks suspicious to me. Can anyone explain the lammps output or
point out if I have made a mistake in the above approximation?
the two input files are pasted below
in.cnt_test
# initialization Section
units real
atom_style atomic
pair_style airebo 3.0 0 0
boundary f f p
read_data ${datafile}
pair_coeff * * /home/haibin/lammps/lammps-8Feb10/potentials/CH.airebo C
neighbor 2.0 bin
neigh_modify delay 5 check yes
timestep 0.5
thermo_style custom step temp etotal pe ke
group cnt type = 1
thermo 10
velocity cnt create 0.0 87287
fix 1 cnt nve
dump 1 cnt atom 10 dump.cnt
dump 2 cnt xyz 10 dump.xyz
run 2000
data.cnt
112 atoms
1 atom types
0 30 xlo xhi
0 30 ylo yhi
0 11.2709 zlo zhi
Masses
1 12.0
Atoms
1 1 13.108954 18.91002 0.737975001
2 1 13.495222 19.168116 2.079749
3 1 14.791809 19.663049 2.348104
4 1 11.458981 15.716186 1.274685001
5 1 11.729735 17.077358 1.543040001
6 1 12.155513 17.901532 0.469620999
7 1 13.298468 12.155513 0.469620999
8 1 12.28998 13.108954 0.737975001
9 1 12.754013 18.610298 3.153167999
10 1 13.108954 18.91002 4.494941999
11 1 14.341974 19.547013 4.763296999
12 1 15.251808 19.72799 3.689878
13 1 11.536951 14.791809 2.348104
14 1 11.47201 15.251808 3.689878
15 1 11.588659 16.634736 3.958233
16 1 11.919482 17.501401 2.884814001
17 1 14.122642 11.729735 1.543040001
18 1 13.698599 11.919482 2.884814001
19 1 12.589702 12.754013 3.153167999
20 1 12.031884 13.495222 2.079749
21 1 18.091046 12.28998 0.737975001
22 1 17.704778 12.031884 2.079749
23 1 16.408191 11.536951 2.348104
24 1 15.483814 11.458981 1.274685001
25 1 19.741019 15.483814 1.274685001
26 1 19.470265 14.122642 1.543040001
27 1 19.044487 13.298468 0.469620999
28 1 17.901532 19.044487 0.469620999
29 1 18.91002 18.091046 0.737975001
30 1 12.434861 18.272721 5.568361001
31 1 12.754013 18.610298 6.910135
32 1 13.907959 19.38134 7.17849
33 1 14.791809 19.663049 6.105071001
34 1 11.652987 14.341974 4.763296999
35 1 11.536951 14.791809 6.105071001
36 1 11.498027 16.179102 6.373426001
37 1 11.729735 17.077358 5.300006999
38 1 14.565264 11.588659 3.958233
39 1 14.122642 11.729735 5.300006999
40 1 12.927279 12.434861 5.568361001
41 1 12.28998 13.108954 4.494941999
42 1 18.445987 12.589702 3.153167999
43 1 18.091046 12.28998 4.494941999
44 1 16.858026 11.652987 4.763296999
45 1 15.948192 11.47201 3.689878
46 1 19.663049 16.408191 2.348104
47 1 19.72799 15.948192 3.689878
48 1 19.611341 14.565264 3.958233
49 1 19.280518 13.698599 2.884814001
50 1 17.077358 19.470265 1.543040001
51 1 17.501401 19.280518 2.884814001
52 1 18.610298 18.445987 3.153167999
53 1 19.168116 17.704778 2.079749
54 1 15.716186 19.741019 1.274685001
55 1 12.155513 17.901532 7.983553999
56 1 12.434861 18.272721 9.325327998
57 1 13.495222 19.168116 9.593682999
58 1 14.341974 19.547013 8.520264
59 1 11.81866 13.907959 7.17849
60 1 11.652987 14.341974 8.520264
61 1 11.458981 15.716186 8.788619
62 1 11.588659 16.634736 7.715200001
63 1 15.020898 11.498027 6.373426001
64 1 14.565264 11.588659 7.715200001
65 1 13.298468 12.155513 7.983553999
66 1 12.589702 12.754013 6.910135
67 1 18.765139 12.927279 5.568361001
68 1 18.445987 12.589702 6.910135
69 1 17.292041 11.81866 7.17849
70 1 16.408191 11.536951 6.105071001
71 1 19.547013 16.858026 4.763296999
72 1 19.663049 16.408191 6.105071001
73 1 19.701973 15.020898 6.373426001
74 1 19.470265 14.122642 5.300006999
75 1 16.634736 19.611341 3.958233
76 1 17.077358 19.470265 5.300006999
77 1 18.272721 18.765139 5.568361001
78 1 18.91002 18.091046 4.494941999
79 1 15.251808 19.72799 11.203812
80 1 11.919482 17.501401 10.398747
81 1 13.907959 19.38134 10.935457
82 1 12.031884 13.495222 9.593682999
83 1 11.81866 13.907959 10.935457
84 1 11.47201 15.251808 11.203812
85 1 11.498027 16.179102 10.130392
86 1 15.483814 11.458981 8.788619
87 1 15.020898 11.498027 10.130392
88 1 13.698599 11.919482 10.398747
89 1 12.927279 12.434861 9.325327998
90 1 19.044487 13.298468 7.983553999
91 1 18.765139 12.927279 9.325327998
92 1 17.704778 12.031884 9.593682999
93 1 16.858026 11.652987 8.520264
94 1 19.38134 17.292041 7.17849
95 1 19.547013 16.858026 8.520264
96 1 19.741019 15.483814 8.788619
97 1 19.611341 14.565264 7.715200001
98 1 16.179102 19.701973 6.373426001
99 1 16.634736 19.611341 7.715200001
100 1 17.901532 19.044487 7.983553999
101 1 18.610298 18.445987 6.910135
102 1 15.948192 11.47201 11.203812
103 1 19.280518 13.698599 10.398747
104 1 17.292041 11.81866 10.935457
105 1 19.168116 17.704778 9.593682999
106 1 19.38134 17.292041 10.935457
107 1 19.72799 15.948192 11.203812
108 1 19.701973 15.020898 10.130392
109 1 15.716186 19.741019 8.788619
110 1 16.179102 19.701973 10.130392
111 1 17.501401 19.280518 10.398747
112 1 18.272721 18.765139 9.325327998
Thanks
Haibin
Haibin Chen Ph.D.
Mechanical Engineering Dept
Carnegie Mellon University
Pittsburgh, Pa, 15213
