High Resolution Euv Emission Spectroscopy of the N 2 C ’ V ’ = 3 and 4 Levels by Electron Impact

A high resolution36 m~ (FWHM), optically thin emission studyof the Nz c’ lX,,+ (4,3) and (3,2) Rydberg bands excited by electron impact at 100 eV has been completed in the extreme ultraviolet (EUV). A model of the perturbed rotational line intensity distribution of the bands shows the effects of electronic state mixing between the c’ lZU+ Rydberg state and the b’ lZU+ valence state. By normalizing the model to the published predissociation yield for J’ =9 the laboratory spectrum can be used to determine the predissociation yields for each rotational level of v’ =3 and 4. Based on a 150/. accuracy of the model fit to the measured signal intensities it is found that the predissociation yield of each c’ rotational level increases as the percentage of b’ lXV+ character increases. The mean predissociation yields for c’ v’= 3 and 4 levels are 0.42 and 0.54, respectively at 300 K. The J’-dependent predissociation yields indicate that the emission cross section is a function of temperature. The remainder of the bands forming the v“ progressions (v”= O to 5) from v’= 3 and(v”== O to 6) from v’ = 4 were studied at 64 m~ (FWHM) resolution. Using this composite spectrum of the two progressions the electron impact emission cross sections of the N2 c’ v’ =3 and 4 levels at 300 K were determined and compared to previous results.