When I calculate the temperature of water in a region, the output temperature was alway lower than the expected one.
The input file was like this:
units real
atom_style full
boundary p p p
read_data 00.data.lammps
group water type 1 2
bond_style harmonic
bond_coeff 1 450 0.9572
angle_style harmonic
angle_coeff 1 55 104.52
pair_style lj/cut/coul/long 12.0
pair_coeff 1 1 0.1521 3.15061 12.000
pair_coeff 1 2 0.0836 1.77530 12.000
pair_coeff 2 2 0.0460 0.40000 12.000
kspace_style pppm 0.0001
special_bonds lj/coul 0.0 0.0 0
neighbor 2.0 bin
neigh_modify delay 0 one 2000 check yes
timestep 1.0
region temp1 block INF INF INF INF -15 15 units box
compute Tregion1 water temp/region temp1
velocity water create 300.0
min_style cg
min_modify dmax 1.0
minimize 0.01 0.001 1000 1000000
thermo_style custom step temp etotal press c_Tregion1
thermo_modify flush yes line one
thermo 100
fix regidwater water shake 0.0001 10 10 b 1 a 1
fix 2 water npt temp 300.0 300.0 100.0 z 1.00 1.00 1000.0
run 500000
unfix 2
I found it is because the presence of ‘fix regidwater water shake 0.0001 10 10 b 1 a 1’. If this command was deleted, temperature of region ‘temp1’ was 300K.
Why? Are there something wrong with shake?
Thanks,
Hangyan
2011-09-24