Oak Ridge National Laboratory

Physics Division

Physics Division Seminars

Physics Division Seminars bring us speakers on a variety of physics related subjects. Usually these are held in the Building 6008 large Conference Room, at 3:00 pm on the chosen day, but times and locations may vary. For more information, contact our seminar chairman,

Alfredo Galindo-Uribarri
Tel (Office): (865) 574-6124  (FAX): (865) 574-1268

Fri., November 14, 2008, at 3:00 p.m. (refreshments at 2:40 p.m.)

Where Have All the Phonons Gone? The Double Vacuum, Phonon-less Nuclei and the Demise of the Bohr Hamiltonian

John Sharpey-Schafer, iThemba Labs, Cape Town, South Africa
Building 6008 Conference Room

It has recently become clear that the first excited 0+ states in the N = 90 and N = 88 nuclei are not β-vibrational excitations but are rather a "second vacuum" state in the style of the "pairing isomers" described by Ragnarsson and Broglia. This second vacuum │02+> has γ and octupole vibrations built upon it in the same manner as the ground-state vacuum │01+ >. There is no sign of β-vibrations, which must be above 1.5 MeV in excitation energy near the particle-hole excitations of │01+ >.

This is very bad news for both the compilers of nuclear data, the writers of textbooks, and for the authors of the flurry of publications during the last decade basing their interpretation of the structure of the rare-earth transitional nuclei on the Bohr Hamiltonian.

The relevant data on Gd and Sm nuclei will be presented and the consequences for current theories of the structure of the Transitional Rare Earth nuclei will be discussed.