Bremsstrahlung in $\alpha$ Decay
  A quantum mechanical analysis of the bremsstrahlung in $\alpha$ decay of $^{210}$Po is performed in close reference to a semiclassical theory. We clarify the contribution from the tunneling, mixed, outside barrier regions and from the wall of the inner potential well to the final spectral distribution, and discuss their interplay. We also comment on the validity of semiclassical calculations, and the possibility to eliminate the ambiguity in the nuclear potential between the alpha particle and daughter nucleus using the bremsstrahlung spectrum. 
N. Takigawa, Y. Nozawa, K. Hagino, A. Ono, and D.M. Brink