Quasiclassical description of bremsstrahlung accompanying α decay including quadrupole radiation

We present a quasiclassical theory of alpha decay accompanied by bremsstrahlung with a special emphasis on the case of Po-210, with the aim of finding a unified description that incorporates both the radiation during the tunneling through the Coulomb wall and the finite energy E-gamma of the radiated photon up to E-gamma similar to Q(alpha)/root eta, where Q(alpha) is the alpha-decay Q-value and eta is the Sommerfeld parameter. The corrections with respect to previous quasiclassical investigations are found to be substantial, and excellent agreement with a full quantum mechanical treatment is achieved. Furthermore, we find that a dipole-quadrupole interference significantly changes the alpha-gamma angular correlation. We obtain good agreement between our theoretical predictions and experimental results.