Microscopic analysis of nuclear quantum phase transitions in the N≈90 region

作者：Z. P. Li, Tamara Nikšić, D. Vretenar, Jie Meng, G. A. Lalazissis, Peter Smith Ring · 发表于：Physical Review C · 年份：2009 · DOI：10.1103/physrevc.79.054301 · 被引用次数：174 · 研究领域：Nuclear physics research studies、Quantum Chromodynamics and Particle Interactions、Advanced Chemical Physics Studies

The analysis of shape transitions in Nd isotopes, based on the framework of relativistic energy-density functionals and restricted to axially symmetric shapes in T. Nik\ifmmode \check{s}\else \v{s}\fi{}i\ifmmode \acute{c}\else \'{c}\fi{}, D. Vretenar, G. A. Lalazissis, and P. Ring [Phys. Rev. Lett. 99, 092502 (2007)], is extended to the region $Z=60,62,64$ with $N\ensuremath{\approx}90$ and includes both $\ensuremath{\beta}$ and $\ensuremath{\gamma}$ deformations. Collective excitation spectra and transition probabilities are calculated starting from a five-dimensional Hamiltonian for quadrupole vibrational and rotational degrees of freedom, with parameters determined by constrained self-consistent relativistic mean-field calculations for triaxial shapes. The results reproduce available data and show that there is an abrupt change of structure at $N=90$ that can be approximately characterized by the X(5) analytic solution at the critical point of the first-order quantum phase transition between spherical and axially deformed shapes.