“…Simple analytical solutions may be obtained, however, under the condition E , -E, >> k-1, k2 (215) (E, and E,,, are any two eigenvalues of H), i.e., if there are no near degeneracies of (TI')-pair energy eigenstates as compared to their width. The following result is obtained for yTT: which was originally suggested by Merrifield on intuitive arguments.7I It corresponds to a superposition of independently decaying energy eigenstates with a specific annihilation rate constant of k21Si12, proportional to their singlet character (cf.…”