how to calculate a1, a2, a3 in lattice custom command?

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1

hi every body

I read the previous mailing list of lattice custom command on B19’NiTi. i don’t know how to calculate a1, a2, a3.

i study the lattice command in manual, but it’s very ambiguous for me. please help me and explain about this.

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

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)


Ni
lattice    custom 2.88 a1 1.585 0.0 -0.230 a2 0.0 1.0 0.0 a3 0.0 0.0 1.428 &
                           basis 0.472 0.0 0.580 basis 0.086 0.5 0.475 
region supercell block 0 1 0 1 0 1 units lattice
create_box    2 supercell
create_atoms 1 region supercell

#Ti
lattice    custom 2.88 a1 1.585 0.0 -0.230 a2 0.0 1.0 0.0 a3 0.0 0.0 1.428 &
                           basis 0.0 0.0 0.0 basis 0.558 0.5 0.055 
create_atoms 2 region supercell


thanks.
2

See section 6.12 of the manual which may help you. For
the lattice command, a1, a2, a3 are the edge vectors of the unit
cell. Those are similar to the box edge vectors discussed in section
6.12 for a general triclinic box.

Steve