Robust upper limit on the neutron single-particle energy of the $i_{13/2}$ orbit
The upper limit of the neutron i13/2 single-particle energy (εi13/2) is estimated in the random quasiparticle ensemble with single-particle energies. The εi13/2 distributions under constraints from 134, Te and 136, Xe spectra demonstrate that the i13/2 single-particle state can be physically mixed with the f7/2 ⊗ 3 ` configuration only if εi13/2 < 3 MeV. Thus, our ensemble calculation suggests a robust upper limit of 3 MeV.