self_rf.inp X-PLOR produced the following list of highest rotation function peaks:
! index, psi, phi, kappa, RF-function ( 0.35) 1 0.000 0.000 180.000 4.9837 123 90.000 0.000 180.000 4.4721 1399 174.000 0.000 170.000 2.5059 1481 90.000 84.000 170.000 2.4751 1492 6.000 0.000 170.000 2.4690 ...cleary indicating the presence of a non-crystallographic symmetry twofold element at (=90, =0, =180). This twofold element is visible in the contour plot shown in Fig. 19.2 as well: