Semiclassical resonance eigenvalues

The calculation of the widths (rates) of tunneling of these vibrational levels has been accomplished recently via semiclassical 11 17 18] as well as quantum 11 19 20] theory. The calculations for He employed extremely accurate PES [1 2 3], since tunneling widths turn out to be very sensitive to the shape of the potential HI. This can be seen in the difference between our results on Be 117] and those of Bauschlicher and Rosi 118]. An important theoretical result from the work of refs 2, 19 and 20 is the fact that the quantum approach of Babb and Du 119] yields reliable results for widths of the order of 10 a.u., something which proved impossible in the case of numerical solution of the complex eigenvalue resonance equation satisfied by the decaying vibrational levels 11 20]. 

---