Unified description of 2<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msubsup><mml:mrow/><mml:mn>1</mml:mn><mml:mo>+</mml:mo></mml:msubsup></mml:math>states within the deformed quasiparticle random-phase approximation

We describe low-lying collective states in deformed even-even nuclei within a deformed quasiparticle random-phase approximation (dQRPA) by using a single-particle basis with good angular momentum. The statistical factors, accounting for the level occupancy, appear in the dQRPA in a natural way as rotation coefficients that take the intrinsic system to the laboratory system. We have used our model by performing a systematic analysis of E2 transitions from the first ${2}^{+}$ state to the ground state for all superfluid nuclei in the range $50&lt;Z\ensuremath{\le}100$ by using a common charge polarization parameter $\ensuremath{\chi}=0.2$. In spite of its similarity to the QRPA, this method is able to describe in an unified way gross features of electromagnetic transitions from vibrational to rotational nuclei.