For complex 1 and 4, the transition-magnetic-moment matrix elements between the ground state KDs are negligibly small i.e., 0.0007 and 0.009 respectively, ruling out the possibility of QTM through the ground state in these complexes. In addition to this, the calculated transition-magnetic-moment matrix element between the ground and first excited KDs of opposite magnetic moments are also very small in magnitude (0.0008 and 0.01 for 1 and 4 respectively), implying slow Orbach relaxation. However, the large transversalmagnetic-moment (0.32 for 1 and 1.1 for 4) for the first excited state suggests relaxation to be operative through first excited state via TA-QTM.