Heterogeneous Nucleation of Ice on Carbon Surfaces

Science Talk
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1

I am currently working on reproduce the results of your paper ‘Heterogeneous Nucleation of Ice on Carbon Surfaces ’,here:https://doi.org/10.1021/ja411507a, and I have encountered an issue that I was hoping you could help me with.

The issue I am facing is as follows:
1.Water drops can’t form contact angle on carbon plate.

2.Only a few water molecules have q6>0.58 during cooling process.

My in file and potential function file are as follows

Initialization

processors 2 2 4
units metal
atom_style full
boundary p p p

read_data shuidiC.data

Potentials

pair_style hybrid sw threebody on sw threebody off
pair_coeff * * sw 1 mW.sw NULL mW
pair_coeff 1 1 sw 2 mW.sw C mW
pair_coeff 1 2 sw 2 mW.sw C mW
group water type 2

timestep 0.01

Neighbor settings

neighbor 2.0 bin
neigh_modify delay 5 every 1
velocity water create 300 87287 loop all dist gaussian
compute Tdroplet water temp
compute q6 water orientorder/atom degrees 1 6 cutoff 3.5
thermo 100
thermo_style custom step temp c_Tdroplet

dump 1 all custom 5000 dump.meltq401 id type mol x y z mass q
dump 2 water custom 100000 dump.q6 id type mol x y z mass q c_q6[1]
#fix zwalls all wall/reflect/stochastic diffusive 23424 zlo 0.0 210 0.1 0.1 0 zhi EDGE 210 0.1 0.1 0
#fix zwalls all wall/reflect/stochastic diffusive 23424 zlo 0.0 160 0.1 0.1 0
fix 1 water nvt temp 300 300 0.1
run 10000
unfix 1
fix 2 water nvt temp 300 200 0.1

Velocity initialization

run 10000000

Monoatomic water potential from Molinero, Valeria, and Emily B. Moore. “Water modeled as an intermediate element between carbon and silicon.” The Journal of Physical Chemistry B 113.13 (2008): 4008-4016 (https://doi.org/10.1021/jp805227c)

Converted by Rodrigo Freitas

format of a single entry (one or more lines):

element 1, element 2, element 3,

epsilon, sigma, a, lambda, gamma, costheta0, A, B, p, q, tol

mW mW mW 0.268381 2.3925 1.8 23.15 1.2 -0.333333333333 7.049556277 0.6022245584 4 0 0
C C C 0 0 0 0 0 0 0 0 0 0 0
C mW mW 0.0056 3.2 1.8 0 0 0 7.049556277 0.6022245584 4 0 0
C C mW 0.0056 3.2 1.8 0 0 0 7.049556277 0.6022245584 4 0 0
C mW C 0.0056 3.2 1.8 0 0 0 7.049556277 0.6022245584 4 0 0
mW C C 0.0056 3.2 1.8 0 0 0 7.049556277 0.6022245584 4 0 0
mW mW C 0.0056 3.2 1.8 0 0 0 7.049556277 0.6022245584 4 0 0
mW C mW 0.0056 3.2 1.8 0 0 0 7.049556277 0.6022245584 4 0 0

Thank you very much in advance,and I am looking forward to your reply.

Best regards,
Shaopeng Li

2

Could you let us know if the script above is meant to be an exact replication of the cited paper? Or, if not, what modifications have you made between the cited paper and your supplied script?

3

Yes, this is the exact reproduction of this paper.

4

It is not. For example, you use a 10fs time step, while the paper say 5fs for open systems and 10fs only for bulk systems. Also, your neighbor list settings are extremely aggressive.

5

What should be the correct neighbor list setting? This setting is not mentioned in the paper.