Transition frequencies in the lower energy spin-ladder ²Π_1/2 were reported by
(1) M. C. McCarthy, A. J. Apponi, C. A. Gottlieb, and P. Thaddeus, 2001, J. Chem. Phys. 115, 870.
The value of A_SO was assumed to be the same as the one calculated for SiC₃N.
Prediction in the lower energy spin-ladder may be reliable up to 120 GHz or even higher. Predictions in the higher energy spin-ladder ²Π_3/2 should be viewed with very great caution.
The dipole moment is from an ab initio calculation by
(2) H.-Y. Zhao, L. Wang, J. Li, Y. Liu, Y.-C. Li, and S.-L. Qin, 2012, Comput. Theor. Chem. 994, 19.