NEW RESULTS IN THE THEORY OF NON-AXIAL NUCLEI

Journal Article · Sat Jul 01 04:00:00 EDT 1961 · Izvest. Akad. Nauk. S.S.S.R., Ser. Fiz.

OSTI ID:4839247

Davydov, A S

If the shape of a nucleus is approximated by an ellipsoid, two parameters beta (O < beta ) and gamma (O < gamma < pi /3) will then determine the shape of the nucleus at constant volume. With the addition of the three Euler angles theta /sub 1/, theta /sub 2/ and theta /sub 3/, there are five dynamic variables which in the simplest model characterize the collective motions in even-even nuclei. Various theories of the collective excitations of even-even nuclei with different types of approximation are reviewed. It is noted that the spectrum of rotational states becomes quite complex if it is assumed that the equilibrium shape of the nucleus does not have axial symmetry. This theory with an adiabatic approximation explains a number of experimental facts. The relative position of the levels and the probability of E2-transitions between the levels depends only on the single parameter gamma which is determined from the ratio of the energies of two excited states with a spin of 2. However, rotation of the nucleus is associated with a change in internal state of the nucleus. The internal excitations are determined by the dynamic variables beta and gamma which can be expressed by two parameters: a parameter mu indicating the deviation from adiabatic conditions, and the parameter gamma indicating the non-symmetry. These parameters can be determined if the energies of three excited states of the nucleus are known. The position of other excited states, the spins and probabilities of the electromagnetic transitions between the states, can be determined from values of mu and gamma . The general case of quadrupole excitations of even-even nuclei is considered. Here all five quantities beta , gamma , theta /sub 1/, theta /sub 2/ and theta /sub 3/ are considere d as dynamic variables. Since the type of collective excitations of even-even nuclei depends on the shape of the nucleus in the ground state, the cases of a spherical nucleus ( beta /sup 0/ = 0) and of a non-spherical nucleus are considered tions of even-even nuclei depends on the shape of the nuseparately. It is pointed out that the collective excitations of negative parity observed in even-even nuclei have not been analyzed yet, and that there is no quantitative theory for odd and odd-odd nuclei. (TTT)

• Research Organization: Moscow State Univ.
• NSA Number: NSA-15-030007
• OSTI ID: 4839247
• Journal Information: Izvest. Akad. Nauk. S.S.S.R., Ser. Fiz., Journal Name: Izvest. Akad. Nauk. S.S.S.R., Ser. Fiz. Vol. Vol: 25
• Country of Publication: Country unknown/Code not available
• Language: Russian

Related Subjects

COLLECTIVE MODEL
DIFFERENTIAL EQUATIONS
ELECTROMAGNETIC FIELDS
ENERGY LEVELS
EVEN EVEN NUCLEI
EXCITATION
MULTIPOLARITY
MULTIPOLE RADIATION
NUCLEAR MODELS
NUCLEAR STRUCTURE
NUCLEAR THEORY
NUCLEI
PARITY
PHYSICS
QUADRUPOLES
QUANTUM MECHANICS
RADIATIONS
ROTATION
SPECTRA
SPIN
TRANSIENTS