 Alpha-particle assault frequency

In a semiclassical escape model, an alpha-particle assault frequency is the interior rate scale multiplying the barrier transmission probability. Confinement alone gives $p\sim \hslash /L$ and hence $\nu \sim \hslash /(m_{\alpha }{L}^2)$ up to geometric factors. Counting encounters with either wall differs by a factor of two from returns to one wall. A stationary bound wavefunction does not itself follow a classical collisional trajectory.