High resolution emission spectroscopy of the A (1)Pi-X (1)Sigma(+) fourth positive band system of CO excited by electron impact

We report electron-impact-induced medium resolution fluorescence spectra of CO [310 m Angstrom and 366 m Angstrom full width at half maximum (FWHM)] a t 100 eV over the spectral region from 1300 to 2050 Angstrom. Features in t he far ultraviolet (FUV) emission spectra correspond to the Fourth Positive band system of CO (A (1)Pi - X (1)Sigma(+)), together with atomic multiple ts from C and O and their ions. The absolute electronic transition moment a s a function of internuclear distance was determined from relative band int ensities scaled to oscillator strength measurements. A model of the vibroni c structure of the band system was developed using the laboratory measureme nt of the electronic transition moment. In addition, we have obtained high resolution spectra (approximate to 34 m Angstrom FWHM) of the CO (A-X) (5,1 ) band at 1435 Angstrom and the (3,0) band at 1447 Angstrom and accurately modeled the rotational line structure. The excitation function of the (0,1) band at 1597 Angstrom was measured in the electron impact energy range fro m threshold to 750 eV and normalized at 100 eV using the relative flow tech nique with the standard NI (1200 Angstrom) cross section from dissociative excitation of NS The CO (A-X) band system emission cross section was establ ished from a measurement of the relative band intensities of CO at 100 eV. The total Fourth Positive band system cascade cross section, arising from ( B --> A) and (C --> A) transitions, is similar to 6% Of the emission cross section at 100 eV The high resolution line profile of the 1152 Angstrom ato mic O multiplet (D-1(0)-D-1) resulting from dissociative excitation of CO w as measured at similar to 22 m Angstrom FWHM. Kinetic energy distributions of the atomic O fragments at 30 eV and 100 eV impact energies were obtained from an analysis of the deconvolved true line profiles.