How to get position vector of atoms in each modes

GULP
1

Hello,

I’d like to get position of atoms depending on each mode

I could get mode and equilibrium positions(r0) information but i could not get the infor about the position(r) of atoms at the each mode , eventhough i look up them in the help

or How could i get displacement(d) of atoms at each mode?
like this: r = r0+d

Thanks

2

I think the issue here is what you think is happening. In harmonic lattice dynamics the atoms don’t move and so have the same position as the equilibrium structure regardless of mode. Vibration just creates a distribution of the atom position around the equilibrium, but in the harmonic case the mean is the same as the equilibrium position.

1 Like
3

Thanks so much for your reply !

I got it for your meaning.

Then, could normal mode coordinates be got directly by gulp?

Thanks prof. Julian

4

Just add the “eigenvector” keyword and you’ll get the directions for every vibrational mode.