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.**