The correlation between the $E1\mathrm{}$ transition strengths of the $1_1^{-}\to 0_1^{+}\gamma$ transition and the $3_1^{-}\to 2_1^{+}\gamma$ transition in heavy vibrational nuclei is investigated. For a given nucleus the $B\left(E1\mathrm{}\right)\mathrm{}$ values are equal within a factor of 2, although for different nuclei these values can differ by two orders of magnitude. This correlation points to a common origin of these $E1\mathrm{}$ strengths, which supports the quadrupole-octupole coupled two-phonon interpretation of the $1_1^{-}$ state in vibrators. The observations can be accounted for within a factor of 2 by the simple bosonic phonon picture in the collective model.

• Received 10 December 1998

DOI:https://doi.org/10.1103/PhysRevC.59.2941