Regarding random allocation of atoms

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1

Hi all,

I am trying to simulate Copper beryllium structure in which Be is 2%. Be is dispersed in the whole copper material. Copper is FCC lattice and Be atoms are introduced in some of the lattices upto 2%.

lattice custom 1 a1 3.615 0 0 a2 0 3.615 0 a3 0 0 3.615 &

 basis   0.0     0.0     0.0     &
        basis   0.5     0.5     0.0     &
        basis   0.5     0.0     0.5     &
        basis   0.0     0.5     0.5     &
        basis   0.5     0.5     0.5

region box block 0 47.606 0 47.606 0 12.994

create_box 2 box #2 is number of atoms

mass 1 63.546

mass 2 9.012

create_atoms 2 region box &

basis 1 1 &

basis 2 1 &

basis 3 1 &

basis 4 1 &

basis 5 2

If i use lattice command and i insert Be atoms at the centre, it will generate a structure which will have 25% Be in whole material(as 1 Be atom for 4 copper atoms in FCC lattice) .

How to ensure Be to be exactly 2% in the copper metal.

2

Hi all,

I am trying to simulate Copper beryllium structure in which Be is 2%. Be is
dispersed in the whole copper material. Copper is FCC lattice and Be atoms
are introduced in some of the lattices upto 2%.

lattice custom 1 a1 3.615 0 0 a2 0 3.615 0 a3 0 0 3.615 &

basis 0.0 0.0 0.0 &
        basis 0.5 0.5 0.0 &
        basis 0.5 0.0 0.5 &
        basis 0.0 0.5 0.5 &
        basis 0.5 0.5 0.5

region box block 0 47.606 0 47.606 0 12.994

create_box 2 box #2 is number of atoms

mass 1 63.546

mass 2 9.012

create_atoms 2 region box &

basis 1 1 &

basis 2 1 &

basis 3 1 &

basis 4 1 &

basis 5 2

If i use lattice command and i insert Be atoms at the centre, it will
generate a structure which will have 25% Be in whole material(as 1 Be atom
for 4 copper atoms in FCC lattice) .

this is a bad procedure, anyway.

How to ensure Be to be exactly 2% in the copper metal.

try using "set type/fraction" instead:

http://lammps.sandia.gov/doc/set.html

axel.