Collapse of the N=28 shell closure in (42)Si.
نویسندگان
چکیده
The energies of the excited states in very neutron-rich (42)Si and (41,43)P have been measured using in-beam gamma-ray spectroscopy from the fragmentation of secondary beams of (42,44)S at 39A MeV. The low 2(+) energy of (42)Si, 770(19) keV, together with the level schemes of (41,43)P, provides evidence for the disappearance of the Z=14 and N=28 spherical shell closures, which is ascribed mainly to the action of proton-neutron tensor forces. New shell model calculations indicate that (42)Si is best described as a well-deformed oblate rotor.
منابع مشابه
Shell structure at N = 28 near the dripline : spectroscopy of 42 Si , 43 P and 44
Measurements of the N = 28 isotones 42Si, 43P and 44S using oneand two-proton knockout reactions from the radioactive beam nuclei 44S and 46Ar are reported. The knockout reaction cross sections for populating 42Si and 43P and a 184 keV γ-ray observed in 43P establish that the d3/2 and s1/2 proton orbits are nearly degenerate in these nuclei and that there is a substantial Z = 14 subshell closur...
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ورودعنوان ژورنال:
- Physical review letters
دوره 99 2 شماره
صفحات -
تاریخ انتشار 2007