Dear lammps-users

I want to ask you a question.

Are all systems of total energy is negative?Can someone explain why the system of the total energy is negative？However, when I simuliated the methanol,I find a strange phenomenon,In the energy minimization,the total energy is negative, but when npt simulation,the total energy is positive,I dont know the reason.

Looking forwarding your reply. Thanks. Jack zhuang

PPPM initialization …

G vector (1/distance)= 0.279756

grid = 15 15 15

stencil order = 5

estimated absolute RMS force accuracy = 0.0144811

estimated relative force accuracy = 4.36094e-05

using double precision FFTs

3d grid and FFT values/proc = 4116 960

Setting up minimization …

Memory usage per processor = 6.93392 Mbytes

Step Temp E_pair E_mol TotEng Press

0 0 3432.9879 983.1922 4416.1801 30347.694

1000 0 -2167.4834 72.727137 -2094.7562 -1097.0266

1003 0 -2167.1703 72.227869 -2094.9425 -1034.1686

Loop time of 34.7178 on 4 procs for 1003 steps with 1500 atoms

Minimization stats:

Stopping criterion = max force evaluations

Energy initial, next-to-last, final =

4416.18012358 -2094.90288435 -2094.94247056

Force two-norm initial, final = 16381.1 7.639

Force max component initial, final = 8937.28 1.54507

Final line search alpha, max atom move = 0.00135656 0.00209597

Iterations, force evaluations = 1003 5001

Pair time () = 18.1113 (52.1671)
Bond time () = 0.645308 (1.85872)

Kspce time () = 12.1217 (34.9151)
Neigh time () = 0.0615801 (0.177373)

Comm time () = 3.36572 (9.69453)
Outpt time () = 7.27177e-05 (0.000209454)

Other time (%) = 0.412091 (1.18697)

FFT time (% of Kspce) = 0.232376 (1.91702)

FFT Gflps 3d (1d only) = 2.36696 8.14115

Nlocal: 375 ave 407 max 326 min

Histogram: 1 0 0 0 0 1 0 0 1 1

Nghost: 3656.5 ave 3763 max 3513 min

Histogram: 1 0 0 0 0 1 0 1 0 1

Neighs: 59689.8 ave 66303 max 47371 min

Histogram: 1 0 0 0 0 0 0 1 1 1

Total # of neighbors = 238759

Ave neighs/atom = 159.173

Ave special neighs/atom = 5

Neighbor list builds = 15

Dangerous builds = 0

PPPM initialization …

G vector (1/distance)= 0.279756

grid = 15 15 15

stencil order = 5

estimated absolute RMS force accuracy = 0.0144811

estimated relative force accuracy = 4.36094e-05

using double precision FFTs

3d grid and FFT values/proc = 4116 960

Setting up run …

Memory usage per processor = 6.21898 Mbytes

Step Temp TotEng Volume den_nvt

1003 298.15 -762.73842 27000 0.49267501

2000 267.51582 391.20822 26776.45 0.49678823

3000 282.28435 486.60513 25652.685 0.518551

4000 287.02643 450.48722 24877.362 0.53471204

5000 297.13156 513.93055 24318.34 0.54700384

6000 300.1999 505.5098 23219.203 0.57289759

7000 297.96665 459.84821 22200.261 0.59919228

8000 305.20581 425.08797 21639.964 0.61470644

9000 295.64187 393.72675 20722.411 0.6419246

10000 299.78943 358.67459 19998.905 0.66514769

11000 309.90264 451.57076 19855.346 0.66995686

12000 299.88925 347.04874 19818.162 0.67121386

13000 293.51759 348.77915 19910.263 0.66810896