64 lines
1.7 KiB
Modula-2
64 lines
1.7 KiB
Modula-2
## This script first constructs a liquid methane structure of a given size. It then uses fix qtb to equilibrate the computational cell to the specified temperature and pressure.
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## This part defines units, methane structure, and atomic information
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#General
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units real
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dimension 3
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boundary p p p
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atom_style charge
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#Lattice
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lattice custom 1.0 &
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a1 3.9783624 0 0 &
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a2 0 3.9783624 0 &
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a3 0 0 3.9783624 &
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&
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basis 0.5 0.5 0.5 &
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basis 0.663 0.663 0.663 &
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basis 0.337 0.337 0.663 &
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basis 0.663 0.337 0.337 &
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basis 0.337 0.663 0.337
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#Computational Cell
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region simbox block 0 3.9783624 0 3.9783624 0 3.9783624 units box
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create_box 2 simbox
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create_atoms 1 box &
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basis 1 1 &
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basis 2 2 &
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basis 3 2 &
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basis 4 2 &
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basis 5 2
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replicate ${x_rep} ${y_rep} ${z_rep}
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#Atomic Information
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mass 1 12.011150
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mass 2 1.007970
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## This part defines the reax pair potential in methane, force field coefficients are specified in "ffield.reax"
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#Pair Potentials
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pair_style reax 10.0 1 1 1.0e-6
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pair_coeff * * ffield.reax 1 2
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#Neighbor Style
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neighbor 2.5 bin
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neigh_modify every 10 delay 0 check no
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## This part equilibrates liquid methane to a temperature of ${temperature}(unit temperatureture) with quantum nuclear effects
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#Initilization
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velocity all create ${temperature} 93 dist gaussian sum no mom yes rot yes loop all
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#Setup output
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thermo_style custom step temp press etotal vol
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thermo 100
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#Colored thermal bath
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fix scapegoat_qtb all nve #NVE does the time integration
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fix methane_qtb all qtb temp ${temperature} damp ${damp_qtb} seed 35082 f_max 0.3 N_f 50 #Change f_max if your Debye frequency is higher
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timestep ${delta_t}
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run 2000 #500 fs
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unfix methane_qtb
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unfix scapegoat_qtb
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