Hi,
I’m trying to calculate self-diffusivity of some binary alloys but not much familiar with the pair_style of “eam” in LAMMPS and meet a problem, I will be very appreciative if you can help answer this.
For example, for a NiPt equimolar system, I used “.in” file like,
“
units metal
atom_style atomic
timestep 0.002
dimension 3
boundary p p p
read_data NiPt_50_1Vac.dat
group Ni type 1
group Pt type 2
pair_style eam
pair_coeff 1 1 Ni_u3.eam
pair_coeff 2 2 Pt_u3.eam
neighbor 1.0 bin
neigh_modify every 1 delay 0 check yes
thermo_style custom step temp press pe ke pxx pyy pzz pxy pyz pxz lx ly lz
thermo_modify flush yes
thermo 10000
variable T1 equal 1000
#variable SEED equal 111
velocity all create {T1} {SEED} mom yes dist gaussian loop all
fix npt_thermostat all npt temp {T1} {T1} 0.2 iso 0.0 0.0 0.2 drag 0.20
run 10000
compute my_msd_1 Ni msd com no
fix my_msd_ave_1 Ni ave/time 1000 1 1000 c_my_msd_1[1] c_my_msd_1[2] c_my_msd_1[3] c_my_msd_1[4] file A_MSD_Ni.dat
compute my_msd_2 Pt msd com no
fix my_msd_ave_2 Pt ave/time 1000 1 1000 c_my_msd_2[1] c_my_msd_2[2] c_my_msd_2[3] c_my_msd_2[4] file A_MSD_Pt.dat
compute my_msd_3 all msd com no
fix my_msd_ave_3 all ave/time 1000 1 1000 c_my_msd_3[1] c_my_msd_3[2] c_my_msd_3[3] c_my_msd_3[4] file A_MSD_All.dat
run 20000000
“
such commands to set up pair coefficients to compute msd values, but the result I got was very unreasonable. Is there anything I messed up? I read the LAMMPS manual and it states that mixing pair interactions will automatically be done so I do not need to specify it. Thanks for your help.
Best regards,
WJ
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