# monoclinic structure

Dear all

I am trying to calculate lattice parameters of B19’ NiTi phase. In several papers, lattice parameters of B19’ phase are represented as following;

a=4.622
b=2.885
c=4.120
beta=96.8 deg

Conventional coordinates of B19’ NiTi phase are reported which are

Ti 1:(0, 0, 0)
Ti 2:(0.558, 0.5, 0.055)
Ni 1:(0.472, 0, 0.580)
Ni 2:(0.086, 0.5, 0.475)

According to the lammps manual the three edge vectors are given by a = (xhi-xlo,0,0); b = (xy,yhi-ylo,0); c = (xz,yz,zhi-zlo), and xz=c*cos(beta).

my question is that can I use these parameters as a1, a2, a3 in lattice custom command?

using above coordinates, I created a lammps code to calculate lattice coordinates of monoclinic structure.

lattice custom 1 a1 4.622 0.0 0.0 a2 0.0 2.885 0.0 a3 -0.486 0.0 4.120

I am still not sure how lammps parameters are defined, especially lo and hi values(i.e xhi, xlo). what is xlo and xhi values? Can I use xlo,ylo,zlo=0.0?

please guide me…

Thanks

Dear all

I am trying to calculate lattice parameters of B19’ NiTi phase. In several papers, lattice parameters of B19’ phase are represented as following;

a=4.622
b=2.885
c=4.120
beta=96.8 deg

Conventional coordinates of B19’ NiTi phase are reported which are

Ti 1:(0, 0, 0)
Ti 2:(0.558, 0.5, 0.055)
Ni 1:(0.472, 0, 0.580)
Ni 2:(0.086, 0.5, 0.475)

According to the lammps manual the three edge vectors are given by a = (xhi-xlo,0,0); b = (xy,yhi-ylo,0); c = (xz,yz,zhi-zlo), and xz=c*cos(beta).

my question is that can I use these parameters as a1, a2, a3 in lattice custom command?

using above coordinates, I created a lammps code to calculate lattice coordinates of monoclinic structure.

lattice custom 1 a1 4.622 0.0 0.0 a2 0.0 2.885 0.0 a3 -0.486 0.0 4.120

I am still not sure how lammps parameters are defined, especially lo and hi values(i.e xhi, xlo). what is xlo and xhi values? Can I use xlo,ylo,zlo=0.0?

please guide me…

This is all explained in the manual and in many discussions on this mailing list. Please keep reading and don’t guess.

Axel

More specifically, see the lattice doc page and the
Section howto 6.12 on triclinic boxes which has
info on different ways to represent a simulation box
and lattices.

Steve