Calculated cross sections and measured rate coefficients for electron-impact excitation of neutral and singly ionized nitrogen

R-matrix calculations for neutral (N I) and singly ionized nitrogen (N II) have been undertaken in the energy region below 50 eV and 180 eV. Spectroscopic measurements were performed in the visible and vacuum-ultraviolent spectral range. Electron densities from 1.8 to 7.0x10(super13) cm(super-3) were obtained from plasma diagnostics, and the rate coefficients were obtained from absolute level densities.