  A semi-classical model based on quantum time concepts is presented for the
evaluation of bremsstrahlung emission probabilities in alpha decay of nuclei.
The contribution to the bremsstrahlung emission from the different regions in
tunneling is investigated using realistic double folded nuclear and Coulomb
potentials. Within this model, the contribution from the radiation emitted in
front of the barrier before tunneling is much larger than that while leaving
the barrier. A comparison with the data on $^{210}$Po shows that the results
are sensitive to the nuclear potential and the rectangular well used in many of
the quantum mechanical approaches can even give qualitatively different
results.
