Modified Embedded Atom Method (MEAM) potential for hydrocarbons (C/H)

From EVOCD
(Difference between revisions)
Jump to: navigation, search
Line 1: Line 1:
These MEAM parameters for elements C and H as well as the diatomic CH are appropriate for energy minimization and reactive molecular dynamics simulations of SATURATED hydrocarbons, where all carbon atoms have the sp3 hybridization (single C-C bonds). At the current state, MEAM cannot handle unsaturated compounds with great accuracy. Furthermore, these C and H parameters are not appropriate for diamond and graphite systems.
+
These MEAM parameters for elements C and H as well as the diatomic CH are appropriate for energy minimization and reactive molecular dynamics simulations of SATURATED hydrocarbons, where all carbon atoms have the sp3 hybridization (single C-C bonds). At the current state, MEAM cannot handle unsaturated compounds with great accuracy. Furthermore, these C and H parameters are not appropriate for diamond and graphite systems. Modification of the MEAM potential to include unsaturated C-C bonds, i.e., double and triple bonds, as well as its parameterization for elements oxygen and nitrogen is ongoing work.
  
 
For the first time, MEAM can be used to simulate hydrocarbons and hydrocarbon/metal systems, since it has a large parameter database for major metals in the periodic table of elements. Since MEAM is a reactive potential, it can also be used to simulate fracture and fatigue in hydrocarbon-based polymers, such as polyethylene and polypropylene and their composites with nanometals as well as polymer/metal interfaces.
 
For the first time, MEAM can be used to simulate hydrocarbons and hydrocarbon/metal systems, since it has a large parameter database for major metals in the periodic table of elements. Since MEAM is a reactive potential, it can also be used to simulate fracture and fatigue in hydrocarbon-based polymers, such as polyethylene and polypropylene and their composites with nanometals as well as polymer/metal interfaces.
 +
 +
MEAM can be run in both DYNAMO and LAMMPS software packages. The C, H, and CH parameters are given below for both DYNAMO and LAMMPS and give equivalent results.
 +
 +
MEAM parameters:
 +
 +
The following two parameter sets can be copied and pasted into two separate text files named library.meam and CH.meam, respectively, in your working directory.
 +
 +
{|border  ="0"
 +
|<pre>
 +
 +
# LAMMPS library.meam file containing MEAM C and H parameters for saturated
 +
# hydrocarbons developed by Sasan Nouranian.
 +
# Reference: Physical Chemistry Chemical Physics, 16(13) (2014):6233-6249.
 +
# This file is used together with the CH.meam file.
 +
 +
# elt        lat    z      ielement    atwt
 +
# alpha      b0      b1      b2          b3    alat    esub    asub
 +
# t0        t1              t2          t3            rozero  ibar
 +
 +
'C' 'dia' 4 6 12.011100
 +
3.600000 4.200000 4.500000 4.300000 4.180000 3.325000 7.370000 0.640000
 +
1.000000 0.500000 0.450000 -3.800000 1.000000 -5.000000
 +
'H' 'dim' 1 1 1.007900
 +
2.038800 2.720000 2.045000 2.250000 3.000000 0.740000 2.363000 2.500000
 +
1.000000 0.200000 -0.400000 0.000001 1.500000 -5.000000
 +
 +
</pre>
 +
|}
 +
 +
{|border  ="0"
 +
|<pre>
 +
# LAMMPS CH.meam file containing the MEAM CH parameters for saturated
 +
# hydrocarbons developed by Sasan Nouranian.
 +
# Reference: Physical Chemistry Chemical Physics, 16(13) (2014):6233-6249.
 +
# This file is used together with the library.meam file.
 +
# Contact: nouranian@gmail.com (Dr. Sasan Nouranian)
 +
 +
rc = 3.000000
 +
delta(1,2) = 2.120000
 +
re(1,2) = 1.020000
 +
delr = 0.1
 +
alpha(1,2) = 3.200000
 +
lattce(1,2) = dim
 +
rho0(1) = 1.000000
 +
rho0(2) = 1.800000
 +
ialloy = 1
 +
emb_lin_neg = 1
 +
bkgd_dyn = 1
 +
erose_form = 0
 +
zbl(1,1) = -100
 +
zbl(1,2) = -100
 +
zbl(2,2) = -100
 +
augt1 = 0
 +
attrac(1,1) = 0.000000
 +
repuls(1,1) = 0.000000
 +
attrac(1,2) = 0.050000
 +
repuls(1,2) = 0.050000
 +
attrac(2,2) = 0.000000
 +
repuls(2,2) = 0.050000
 +
Cmin(1,1,1) = 2.000000
 +
Cmax(1,1,1) = 2.800000
 +
Cmin(1,1,2) = 2.000000
 +
Cmax(1,1,2) = 2.800000
 +
Cmin(1,2,1) = 0.445000
 +
Cmax(1,2,1) = 2.800000
 +
Cmin(1,2,2) = 1.500000
 +
Cmax(1,2,2) = 2.000000
 +
Cmin(2,2,1) = 0.520000
 +
Cmax(2,2,1) = 2.200000
 +
Cmin(2,2,2) = 0.750000
 +
Cmax(2,2,2) = 2.800000
 +
 +
</pre>
 +
|}
  
 
{|border  ="0"
 
{|border  ="0"

Revision as of 15:52, 25 July 2014

These MEAM parameters for elements C and H as well as the diatomic CH are appropriate for energy minimization and reactive molecular dynamics simulations of SATURATED hydrocarbons, where all carbon atoms have the sp3 hybridization (single C-C bonds). At the current state, MEAM cannot handle unsaturated compounds with great accuracy. Furthermore, these C and H parameters are not appropriate for diamond and graphite systems. Modification of the MEAM potential to include unsaturated C-C bonds, i.e., double and triple bonds, as well as its parameterization for elements oxygen and nitrogen is ongoing work.

For the first time, MEAM can be used to simulate hydrocarbons and hydrocarbon/metal systems, since it has a large parameter database for major metals in the periodic table of elements. Since MEAM is a reactive potential, it can also be used to simulate fracture and fatigue in hydrocarbon-based polymers, such as polyethylene and polypropylene and their composites with nanometals as well as polymer/metal interfaces.

MEAM can be run in both DYNAMO and LAMMPS software packages. The C, H, and CH parameters are given below for both DYNAMO and LAMMPS and give equivalent results.

MEAM parameters:

The following two parameter sets can be copied and pasted into two separate text files named library.meam and CH.meam, respectively, in your working directory.


# LAMMPS library.meam file containing MEAM C and H parameters for saturated
# hydrocarbons developed by Sasan Nouranian.
# Reference: Physical Chemistry Chemical Physics, 16(13) (2014):6233-6249.
# This file is used together with the CH.meam file.

# elt        lat     z       ielement     atwt 
# alpha      b0      b1      b2           b3    alat    esub    asub 
# t0         t1              t2           t3            rozero  ibar 

'C' 'dia' 4 6 12.011100 
3.600000 4.200000 4.500000 4.300000 4.180000 3.325000 7.370000 0.640000 
1.000000 0.500000 0.450000 -3.800000 1.000000 -5.000000 
'H' 'dim' 1 1 1.007900 
2.038800 2.720000 2.045000 2.250000 3.000000 0.740000 2.363000 2.500000 
1.000000 0.200000 -0.400000 0.000001 1.500000 -5.000000

# LAMMPS CH.meam file containing the MEAM CH parameters for saturated
# hydrocarbons developed by Sasan Nouranian.
# Reference: Physical Chemistry Chemical Physics, 16(13) (2014):6233-6249.
# This file is used together with the library.meam file.
# Contact: nouranian@gmail.com (Dr. Sasan Nouranian)

rc = 3.000000 
delta(1,2) = 2.120000
re(1,2) = 1.020000
delr = 0.1
alpha(1,2) = 3.200000
lattce(1,2) = dim
rho0(1) = 1.000000
rho0(2) = 1.800000
ialloy = 1
emb_lin_neg = 1
bkgd_dyn = 1
erose_form = 0
zbl(1,1) = -100
zbl(1,2) = -100
zbl(2,2) = -100
augt1 = 0
attrac(1,1) = 0.000000 
repuls(1,1) = 0.000000 
attrac(1,2) = 0.050000 
repuls(1,2) = 0.050000 
attrac(2,2) = 0.000000 
repuls(2,2) = 0.050000 
Cmin(1,1,1) = 2.000000 
Cmax(1,1,1) = 2.800000 
Cmin(1,1,2) = 2.000000 
Cmax(1,1,2) = 2.800000 
Cmin(1,2,1) = 0.445000 
Cmax(1,2,1) = 2.800000 
Cmin(1,2,2) = 1.500000 
Cmax(1,2,2) = 2.000000 
Cmin(2,2,1) = 0.520000 
Cmax(2,2,1) = 2.200000 
Cmin(2,2,2) = 0.750000 
Cmax(2,2,2) = 2.800000 


# Sample LAMMPS input script for the energy minimization of isobutane (methylpropane) (C4H10)
# This file is used with the Isobutane.dat file and the MEAM parameter files.
# Reference: Physical Chemistry Chemical Physics, 16(13) (2014):6233-6249.
# Will reproduce the uncorrected MEAM value for Isobutane in Table 3, Column 4 of the paper. 

# ------------------ Initialize Simulation -----------------------
clear
units metal
boundary p p p
atom_style atomic
read_data Isobutane.dat

# --------------- Define Interatomic Potential -------------------
pair_style meam
pair_coeff * * CH_library.meam C H CH.meam C H

# -------------------- Define Output -----------------------------
dump coord all custom 1 Isobutane.dump id type x y z

# ------------------- Run Minimization ---------------------------
minimize 1e-25 1e-25 10000 10000

Personal tools
Namespaces

Variants
Actions
home
Materials
Material Models
Design
Resources
Projects
Education
Toolbox