lammps实例(2).pdf

lammps实例(2).pdf

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Project#4表面与界面能表面与界面能铜的表面能铜的表面能当物体形成表面时，表面上的原子键发生断裂，接近表面的几层原子不再如之前处于平衡状态，从而导致能量的升高，升高的温度便是物体的表面能。

利用LAMMPS做出20*20*40fcc的盒子，删去边缘的原子制造出一段真空层；算出此时体系的总能量0E，然后从中间把盒子切成两半并移至足够远的距离，此时的体系总能量为Efinal，从而表面能：

02finalsurfaceEEA=A为表面的面积（100）面与面与（111）面面如下是输入文件in.surface_Cu_100#LAMMPSCu_Surface_100unitsmetalboundarypppatom_styleatomiclatticefcc3.61regionboxblock020020040create_box1boxcreate_atoms1boxtimestep0.005thermo5pair_styleeam/alloypair_coeff*jin_copper_lammps.setflCuregionboundary1blockINFINFINFINF29.9INFregionboundary2blockINFINFINFINFINF9.9groupboundary1regionboundary1groupboundary2regionboundary2groupboundaryunionboundary1boundary2delete_atomsgroupboundaryneighbor0.6binneigh_modifyevery5delay0checkyescompute3allpe/atomcompute4allke/atomcompute5allcoord/atom3.0dump1allcustom100dump.atomidxsyszsc_3c_4c_5dump_modify1format%d%16.9g%16.9g%16.9g%16.9g%16.9g%gmin_stylesdminimize1.0e-301.0e-15100010000variableEequalpeprint-E=$E-run0regiondownblockINFINFINFINFINF19.94regionupblockINFINFINFINF19.95INFgroupupregionupgroupdownregiondowndisplace_boxallzdelta040unitslatticeremapnonedisplace_atomsupmove0040unitslatticeminimize1.0e-301.0e-2010000100000print-SURFACE-E=$E-Plane（100）（111）Surfaceenergy（2/mJm）13301228Plane（111）Plane（100）镁的镁的hcp/fcc界面能界面能计算镁的hcp/fcc界面能比较有趣。

正如我们所知，镁是hcp结构的金属，它是按ABABABABAB所排列的；当我们进行一系列移动之后得到ABABCABCAB，从而产生镁的hcp/fcc界面。

如下是输入文件in.hcp_fcc_vac#LAMMPShcp_fcc_Mgunitsmetalboundarypppatom_styleatomiclatticecustom4.5198a11.22474487139158904900a200.70710678118654752440a3001.1476basis0.00.00.0basis0.50.50.0basis0.333333333333333333330.00.5basis0.833333333333333333330.50.5regionboxblock0606036create_box1boxcreate_atoms1boxpair_styleeam/alloypair_coeff*mg.eam.alloyMgneighbor0.8binneigh_modifyevery5delay0checkyesthermo10variableNequalatomsvariableEequalperegionboundary1blockINFINFINFINF26.9INFregionboundary2blockINFINFINFINFINF8.9groupboundary1regionboundary1groupboundary2regionboundary2groupboundaryunionboundary1boundary2delete_atomsgroupboundarylabeldjvariablexindex17.918.919.920.921.922.923.924.925.9regionup_$xblockINFINFINFINF$xINFgroupup_$xregionup_$xdisplace_atomsup_$xmove-0.333333333333333333333333333333333333333333333333333333300unitslatticenextxjumpin.hcp_fcc_vacdjtimestep0.01regionpartblockINFINFINFINF1224grouppartregionpartcompute3allpe/atomcompute4allke/atomcompute5allcoord/atom3.0dump1partcustom100dump.atomidxsyszsc_3c_4c_5dump_modify1format%d%16.9g%16.9g%16.9g%16.9g%16.9g%gmin_stylesdminimize1.0e-301.0e-1510000100000shellmkdirdump_fcc_hcpshellmvdump.atomdump_fcc_hcp/dump.atomprint-fcc_hcp-N=$NE=$E-delete_atomsgroupalllatticenonelatticecustom4.5198a11.22474487139158904900a200.70710678118654752440a3001.1476basis0.00.00.0basis0.50.50.0basis0.333333333333333333330.00.5basis0.83333333333333333333333333333333333333333333333333330.50.5create_atoms1boxgroupboundary1regionboundary1groupboundary2regionboundary2groupboundaryunionboundary1boundary2delete_atomsgroupboundaryundump1dump1allcustom100dump_hcp.atomidxsyszsc_3c_4c_5dump_modify1format%d%16.9g%16.9g%16.9g%16.9g%16.9g%gmin_stylesdminimize1.0e-301.0e-151000010000print-hcp-N=$NE=$E-shellmkdirdump_hcpshellmvdump_hcp.atomdump_hcp/dump.atomdelete_atomsgroupalllatticenonelatticecustom4.5198a11.22474487139158904900a200.70710678118654752440a3001.1476basis0.00.00.0basis0.50.50.0basis0.333333333333333333330.00.5basis0.833333333333333333330.50.5create_atoms1boxgroupboundary1regionboundary1groupboundary2regionboundary2groupboundaryunionboundary1boundary2delete_atomsgroupboundarylabelddjvariableyindex9.910.911.912.913.914.915.916.917.918.919.920.921.922.923.924.925.9regionup_fcc_$yblockINFINFINFINF$yINFgroupup_fcc_$yregionup_fcc_$ydisplace_atomsup_fcc_$ymove-0.33333333333333333333333333333333333333333333333333333333300unitslatticenextyjumpin.hcp_fcc_vacddjundump1dump1allcustom1000dump_fc.atomidxsyszsc_3c_4c_5dump_modify1format%d%16.9g%16.9g%16.9g%16.9g%16.9g%gmin_stylesdminimize1.0e-301.0e-1510000100000shellmkdirdump_fccshellmvdump_fcc.atomdump_fcc/dump.atomprint-fcc-N=$NE=$E-根据公式：

thcpfcc1E（EE）22A+=+=可以得到：

227.058（mJ/m）=，这与之前所得到结果比较吻合。