A He~I photoelectron spectrum ( ) of carbon monoxide shows three bands:
PHYSICS · Multi-part · Fermi University Physics · Atomic, Molecular & Optical Physics · Molecular structure and spectra · Molecular structure and spectra
Deriving the Spectrum, Ch Electronic spectra of diatomic molecules
Problem
A He I photoelectron spectrum (hν=21.22eV) of carbon monoxide shows three bands:
((a)) a band near 14.01eV with an intense 0-0 line and only one weak neighbouring vibrational line;
((b)) a band near 16.91eV with a long progression of about seven vibrational lines, its maximum well away from the 0-0 line;
((c)) a band near 19.72eV with an intense 0-0 line and one weak neighbour. For each band, predict (i) whether the orbital removed is weakly bonding/nonbonding or strongly bonding, from the length of its Franck-Condon envelope, and (ii) whether the equilibrium bond length of the corresponding CO+ electronic state is close to, or noticeably longer than, that of neutral CO.