Abstract
In our experiments involving the collision of electrons with (), the ionization-efficiency curve of shows no structure which can be obviously related to the direct vibrational spectrum of . In the first-derivative spectrum, however, the major peaks correspond to the major peaks in the photo-ionization spectrum, which strongly suggests, for allowed transitions, a one-to-one correspondence between and . Other peaks no doubt are associated with auto-ionizing states of which can only be reached through channels normally forbidden to photoexcitation. The major valleys can be related to the direct vibrational-excitation thresholds. From these experiments and other published results, we believe that the auto-ionizing lifetime for many states may be long.
- Received 9 January 1967
DOI:https://doi.org/10.1103/PhysRev.167.52
©1968 American Physical Society