LAMMPS experts,
I am running a-quartz simulation with COMB. I am getting volume/SiO2 to be lower than the paper published in 2006. The density seems a bit high at 2.87 g/cc at 300K and 1 atm. Can someone who is very familiar with this potential look at these couple lines of my code to see if there are any obvious errors?
units metal
atom_style full
read_data …/…/quartz.data
pair_style comb
pair_coeff * * …/…/…/…/potentials/ffield.comb O Si
fix 11 all qeq/comb 10 1.0e-6
timestep 0.0001
When I run, I also get this statement before the run:
generating Coulomb integral lookup table …
will not apply over-coordination correction
Perhaps I am just not as experienced with this potential to see a possible flaw in this script. I followed instructions on the doc page but do not seem to be getting results consistent with literature.
Ben
LAMMPS experts,
I am running a-quartz simulation with COMB. I am getting volume/SiO2 to be
lower than the paper published in 2006. The density seems a bit high at 2.87
So is it higher or lower than what you expected? There is no COMB
paper published in 2006.
g/cc at 300K and 1 atm. Can someone who is very familiar with this potential
look at these couple lines of my code to see if there are any obvious
errors?
These lines look alright, but they tell very little. What are more
important are how long have you run, what were the damping factors,
and how the density was obtained (instantaneous, average?)
I get an average around 2.82 g/cc, which is ~6% larger than the
reported value of ~2.65 g/cc.
Ray
When you say you get larger than reported, are you talking about larger than reported experimentally or by the author of that COMB potential?
I am using a timestep of 0.2 fs.
Tdamp is 0.002ps and Pdamp is 0.02ps.
When you use fix qeq, how often do you recalculate the charge?
I meant the paper from 2007.
Ben