Dear Users,
How can I setup a SiO2 structure in LAMMPS? I have taken a low-quartz from: http://cst-www.nrl.navy.mil/lattice/struk/sio2b.html
I tried to set it us as follows:
lattice custom 1.0 &
a1 2.45670000 -4.25512922 .00000000 &
a2 2.45670000 4.25512922 .00000000 &
a3 .00000000 .00000000 5.40520000 &
basis .46990000 0.00000000 .66666667 &
basis 0.00000000 .46990000 .33333333 &
basis -.46990000 -.46990000 .00000000 &
basis .41410000 .26810000 .78540000 &
basis -.26810000 .14600000 .45206667 &
basis -.14600000 -.41410000 .11873333 &
basis .26810000 .41410000 -.78540000 &
basis -.41410000 -.14600000 -.11873333 &
basis .14600000 -.26810000 -.45206667
region box block 0 1 0 1 0 1
create_box 2 box
create_atoms 1 box &
basis 1 1 &
basis 2 1 &
basis 3 1 &
basis 4 2 &
basis 5 2 &
basis 6 2 &
basis 7 2 &
basis 8 2 &
basis 9 2
This gives me a failure Use of region with undefined lattice. The manual says If scale = lattice (the default) for the region command, then a lattice must first be defined via the lattice command. Obviously something is wrong with my region command. What I don’t understand is: I defined a lattice - why cannot I define a region, then? Any hints are welcome 
Best regards:
Gerolf
