However, for complex 3 with positive D value, the ground state KDs has m J = ±1/2 as the projection of total angular momentum. The spin reversal barrier (U ef f ) of 226 cm -1 is reported experimentally. The D value of -62.4 cm -1 and 34.0 cm -1 for 2 and 3 respectively are reported from DDCI3 method by Meng et al. The contrasting negative sign of D is may be due to the issue of intruder states in CASPT2.