# Fortran code for geometry of fcc

1. Oct 23, 2012

### quin

Hi friends . is there any body here who can give me a fortran code for describing fcc lattice and give us the neighbours of each site and also which pay attention to periodic condition ?
thank you for your help my friends.

2. Oct 23, 2012

### Staff: Mentor

I'll say the same thing I said in response to your other post: What have you tried? We are not going to write the code for you, if that's what you had in mind.

3. Oct 23, 2012

### quin

yes dear, you are right but i wanna write a code for geometry of fcc and i wrote it but i dont know how can i apply periodic boundary condition on for cubic? i mean i must connect the topest point to lowest point of lattice i dont know how can i show this?

but i supposed that each site has 12 neighbours and if take an array like this for nearest neighbours :
(number of neighber ,number of site )
foe example: (3,4) shows the third neughbour of 4th spin,
and then try to fill it, i used this way :

if i show each point of fcc with n=i*a1 + j*a2 + k*a3 in which, a1 ,a2, a3 are translation vector , then i ,j ,z are integer numbers
then the cubic dimension is L*L*L and each site of lattice can be shown by :
n=i+j*L+k*L^2

and i can calculate the "n" of all of 12 neighbours of each site. but i dont know how use peridic condition in all of 3 direction of x,y,z?

4. Oct 23, 2012

### Staff: Mentor

Many of us here probably don't know what "fcc lattice" is, so if you can point us to something that describes it, we might be able to help.