In the phenomenological and microscopic boson interaction (IBM), the relative contribution rate of the neutron proton excitation energy has not been studied clearly because of the existence of their degrees of freedom. This study proposes: if some nuclear are the conjugate ones that has equal neutron and proton numbers on same large shell, they should contribute to the excitation energy equal on low lying excited states, this work avoid the big problem of energy allocation evaluation. The low excitation energy spectra for the 6 even even nuclei, 64Ge32, 68Se34, 72Kr36, 76Sr38, 80Zr40 and 84Mo42, are calculated in theory using experimental value of levels on 28~50 nuclear shell, the spectra calculated are well reproduced the experimental measurement of the complex spectra, supporting the above conjecture. The value of levels on 28~50 nuclear shell are thus obtained, the equivalent strength parameters of interactions between neutron proton can be used as a starting point for further research.
