Dear All,
Sorry for bothering everyone. I am now doing simulations about observing the water wetting behavior on PP surfaces. For water I use the tip3p as the potential and for polymer surface I used class 2 (pcff) as force filed. And between water and pp surface, I manually calculated the interaction potential with mixing rule “geometric”.
Here is part of input file
pair_style hybrid lj/cut/coul/cut 10.0 8.5 lj/class2/coul/cut 10.0 8.5
bond_style hybrid harmonic class2
angle_style class2
dihedral_style class2
improper_style class2
dimension 3 #specify the number of dimensions
boundary p p m #says the periodicity in each dimension
read_data data.pptip3p500
pair_coeff 1 1 lj/cut/coul/cut 0.1521 3.1507
pair_coeff 2 2 lj/cut/coul/cut 0.0460 0.4000
pair_coeff 1 2 lj/cut/coul/cut 0.0836 1.7753
pair_coeff 3 3 lj/class2/coul/cut 0.0200000000 2.9950000000
pair_coeff 4 4 lj/class2/coul/cut 0.0540000000 4.0100000000
pair_coeff 5 5 lj/class2/coul/cut 0.0540000000 4.0100000000
pair_coeff 6 6 lj/class2/coul/cut 0.0540000000 4.0100000000
pair_coeff 1 3 lj/cut/coul/cut 0.055154 3.071864
pair_coeff 1 46 lj/cut/coul/cut 0.0906278 3.554477
pair_coeff 2 3 lj/cut/coul/cut 0.0303315 1.0945318
pair_coeff 2 46 lj/cut/coul/cut 0.049840 1.266491
bond_coeff 1 harmonic 450.0000 0.9572
bond_coeff 2 class2 345.0000 -691.8900 844.6000 1.1010
…
…
bond_coeff 8 class2 299.6700 -501.7700 679.8100 1.5300
angle_coeff 1 55.0000 0.0000 0.0000 104.5200
angle_coeff 2 39.6410 -12.9210 -2.4318 107.6600
…
…
angle_coeff 16 41.4530 -10.6040 5.1290 110.7700
group ox type 1
group hy type 2
set group ox charge -0.834
set group hy charge 0.417
minimize 1.0e-4 1.0e-5 1000 10000
timestep 2.0
group water type 1 2
group pp subtract all water
thermo_style custom step temp etotal pe ke evdwl ecoul ebond eangle edihed
thermo 100
fix 1 water shake 1e-6 200 0 b 1 a 1
velocity water create 1.0 1234546 dist gaussian
fix 2 water nvt temp 300.0 300.0 100.0
When I run this input script on HPC, lammps can finish reading the data file and go through the coefficients setting until it meets command “fix shake”
The error information is “Shake determinant = 0.0”
What does this really mean and how can I fix it?
Another thing should mention is that if I run this same script in local desktop with older version of lammps， this error didn’t show up. Instead, total energy, potential energy and vdwl energy in the log file will be “nan”. Will this be related to the “shake determinant” problem?
Thank you very much for your time!
Jing