Abstract:
Although it is generally accepted that Rydberg orbitals are very
large and diffuse, and that electron promotion to a Rydberg orbital is
not too different from ionization of the molecule, analysis of the two
types of transitions proves otherwise. The photoelectron spectrum of the
2B2 (n) ion has very little vibrational structure attached to the origin
band; on the other hand, several of the Rydberg transitions which involve
the promotion of the n(bZ) electron exhibit a great deal of vibrational
activity. In particular, the members of the n=3 Rydberg\ series interact
with and perturb each other through pseudo-Jahn-Teller vibronic coupling.
The vacuum ultraviolet spectrum contains a number of features which are
difficult to explain, and two unusually sharp bands can only be identified
as representing some form of electron promotion in formaldehyde.
