N_pN_n dependence of empirical formula for the lowest excitation energy of the 2^+ states in even-even nuclei

Abstract

We examine the effects of the additional term of the type $\sim e^{-{\lambda }^{\prime }{N}_p{N}_n}$ on the recently proposed empirical formula for the lowest excitation energy of the $2^{+}$ states in even-even nuclei. This study is motivated by the fact that this term carries the favorable dependence of the valence nucleon numbers dictated by the $N_p{N}_n$ scheme. We show explicitly that there is not any improvement in reproducing $E_x(2_1^{+})$ by including the extra $N_p{N}_n$ term. However, our study also reveals that the excitation energies $E_x(2_1^{+})$, when calculated by the $N_p{N}_n$ term alone (with the mass number $A$ dependent term), are quite comparable to those calculated by the original empirical formula.

14 pages, 5 figures

References in corpus (5)

• Empirical Proton-Neutron Interactions and Nuclear Density Functional Theory: Global, Regional and Local Comparisons
• Global study of the spectroscopic properties of the first 2+ state in even-even nuclei
• N_p N_n Scheme Based on New Empirical Formula for Excitation Energy
• Universal Expression for the Lowest Excitation Energy of Natural Parity Even Multipole States
• Origin of $2_1^{+}$ Excitation Energy Dependence on Valence Nucleon Numbers

Cited by in corpus (1)

• Rotational energy term in the empirical formula for the yrast energies in even-even nuclei