[SIESTA-L] problem with optical calculations

[somayeh rudi]

Dear siesta users
      I am trying to calculate the optical properties of graphene. 
I have the .EPSIMG file and i want  to calculate different optical properties 
out of it.
I used the command input < System label.EPSIMG but  siesta asked for length , 
diameter and
 position of antenna elements to be written in  a file that i should specify.
I think there is something wrong because i have no antennas 
I will be thankful if someone help me
with regards 
S.Gholami