The effect of parity and isospin mixing on the nuclear deformation of 6LI.

The nuclear shell theory has been used extensively and rather successfully to describe nuclear structure and other nuclear properties in general. However, the pure shell model has its limitations, and cannot describe some of the microscopic details of nuclear structure. For example, ordinarily 6Li can be best described in the LS coupled shell model. However, the static electric quadrupole moment of 6Li vanishes in pure LS coupling.

A Jastrow-type short range correlation has been introduced into the harmonic oscillator shell model wave function. The intermediate coupling has been used by adding the P and D states to the predominantly ^'^Si ground state wave function, thus mixing different parity and isospin states.

The static electric quadrupole, electric hexadecapole and magnetic dipole moments have been computed for the ground state. The electric quadrupole transition width between the 1+, 0 ground state and the 3+ ,0 first excited state (2.184 MeV) has been computed. The magnetic dipole transition width between the l+,0 ground state and the 0+, 1 second excited state (3.56 MeV) has been fitted. The best correlated, parity and isospin mixed wave function yields Q = -0.621 e•mb (-3.57%), µ = 0.892 nm (8.52%), hexadecapole = -0.112 e•fm^4 and r(E2) = 4.31 x lO^-4 eV (-2.05%).