Electron energy-loss spectroscopy of carbon monoxide. II. The energy region 11 to 20 eV

For pt.I see ibid., vol.15, no.12, p.1929-37 (1982). An electron impact spectrometer incorporating a position-sensitive multidetector has been used to study the excited electronic states carbon monoxide in the energy region 11 to 20 eV. A series of peaks previously assigned to one vibrational progression have been resolved into two progressions, one of which has been assigned to a transition to a previously unobserved state. At high impact energy and small scattering angle the spectra observed are in good agreement with previous photoabsorption data. At high scattering angle members of Rydberg series resulting from spin-forbidden transitions have been observed in the energy region below the first ionisation potential. At higher excitation energies several new spectral features have been observed, some of which have been assigned to Rydberg series.