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[求助]
表面摩擦做平衡的若干问题 已有1人参与
本人最近在用LAMMPS做摩擦,模型为z方向上下两个表面,x、y、z方向都赋予周期性边界条件,中间加水。我想在上下表面分别沿x轴正负方向运动的同时能在z方向做npt,使盒子在z方向有一定的伸缩以保证中间用于摩擦的水的压强不变。但是在做平衡时,赋予所有原子初速度并在z方向npt,为上下表面赋予定时位移后模型没能正常运动。请问可能是什么原因?另外脚本有无其它问题?下面是我做平衡的脚本,新手上路,请大家多多批评指正!
##########################
# Initialization
#-------------------------
boundary p p p
units real
#------------------------------
# Force field specifications
#------------------------------
atom_style full
bond_style harmonic
angle_style charmm
dihedral_style charmm
pair_style lj/charmm/coul/charmm 10 12
pair_modify mix arithmetic
neigh_modify every 2 delay 10 check yes
special_bonds charmm
#----------------
# Read geometry
#----------------
read_data solved_d10.data
#---------------------
# Define Groups
#---------------------
group water type 1 10
group wato type 10
group allsulfur type 7
group uppersurf molecule <> 49 96
group lowersurf molecule <> 1 48
group uppersulfur intersect allsulfur uppersurf
group lowersulfur intersect allsulfur lowersurf
group uppernosulfur subtract uppersurf uppersulfur
group lowernosulfur subtract lowersurf lowersulfur
group pControl union lowernosulfur uppernosulfur water
group twosurfs union lowersurf uppersurf
#---------------------
# Fix all sulfur atoms
#---------------------
fix fixsulfur allsulfur setforce 0.0 0.0 0.0
#--------------
# Minimization
#--------------
min_style sd
minimize 0.0 1.0e-8 1000 100000
#-----------------------
# Initialize velocities
#-----------------------
velocity all create 10.0 4928459 rot yes mom yes dist gaussian
#---------------------
# Shake all H atoms
#---------------------
fix shakeH all shake 0.0001 20 0 m 1.0 a 11
#---------------------
## Set Shear Velocity
##---------------------
variable xu equal vdisplace(0.0,0.0001)
variable xl equal vdisplace(0.0,-0.0001)
fix vu uppersurf move variable v_xu NULL NULL NULL NULL NULL
fix vl lowersurf move variable v_xl NULL NULL NULL NULL NULL
#--------------------------------
# Define the integration method
#--------------------------------
fix 1 all npt temp 10.0 300.0 100.0 z 1.0 1.0 1000.0
#-------------------------------
# Customize output infomration
#-------------------------------
thermo 10000
thermo_style multi
dump mydump all atom 10000 trjequil.lammpstrj
restart 500000 res.equil
附件中是模型视图
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