Home › Forums › Hyperfine course › electric quadrupole interaction › case studies / symmetry – task 1 › symmetry axes This topic has 0 replies, 1 voice, and was last updated 1 year, 7 months ago by Robbe Van Duyse. Viewing 1 post (of 1 total) Author Posts March 20, 2023 at 1:10 am #4363 Robbe Van DuyseParticipant Fe-I has 4-fold rotation symmetry in the z-axis (and 2-fold symmetry in x and y) and therefore eta is zero. I think the same is true for the Fe-II and so also eta is zero. Author Posts Viewing 1 post (of 1 total) You must be logged in to reply to this topic. Log In Username: Password: Keep me signed in Log In