fix command/ wiggle/ variance

Hi Everybody,

I want to use fix move command( wiggle or variable) to move a group of atoms to oscillate in both X and Z directions with a Pi/2 phase difference, so the combined trajectory is just like a circle. I could set the wiggle command, but have no idea how to set the Pi/2 phase difference.
Any thoughts or comments are appreciated,

All the best,


You could use the variable option of fix move and write

the equation for x and y with trig functions and phase offsets,
however you wish.