Deformation of very light rare-earth nuclei.

摘要: Gamma-ray spectra of neutron-deficient isotopes between cerium ($Z=58$) and gadolinium ($Z=64$) have been investigated. New bands states were identified in many even-even, odd-$A$, odd-odd nuclei. This Letter reports results on the ground-state even-even nuclei $_{58}^{126}\mathrm{Ce}_{68}$, $_{60}^{128,\phantom{\rule{0ex}{0ex}}130,\phantom{\rule{0ex}{0ex}}132}\mathrm{Nd}_{68,\phantom{\rule{0ex}{0ex}}70,\phantom{\rule{0ex}{0ex}}72}$, $_{62}^{134,\phantom{\rule{0ex}{0ex}}136}\mathrm{Sm}_{72,\phantom{\rule{0ex}{0ex}}74}$, $_{64}^{138,\phantom{\rule{0ex}{0ex}}140}\mathrm{Gd}_{74,\phantom{\rule{0ex}{0ex}}76}$. The systematic trends deformation are presented compared with theoretical predictions. lightest appear to be axially symmetric rotors ${\ensuremath{\epsilon}}_{2}\ensuremath{\gtrsim}0.3$.