In Fig. , the contributions from the EPR transitions between Q ±"/$ and Q ±%/$ are minor on the outer fine structure, while the center sharp peak by the transition between Q &"/$ and Q '"/$ is strong. This weaker fine-structure component is due to the weak selectivity in the spin sublevel population in the presence of the strong J-couplings, as shown in Fig. . However, the sublevel population in Q &"/$ is greater than that in Q '"/$ at any field directions (q, f), because the