  Gamow-Teller strength distributions and beta-decay half-lives in
neutron-deficient Kr and Sr isotopes are investigated within a deformed
quasiparticle random phase approximation. The approach is based on a
selfconsistent Skyrme Hartree-Fock mean field with pairing correlations and
residual separable particle-hole and particle-particle forces. A simple
two-level model is used to mix the nuclear shapes into the physical ground
state. Good agreement with experiment is found with shape mixing coefficients
which are consistent with those obtained phenomenologically from mixing of
rotational bands.
