Cross sections for excitation of the (2s22p23s)4P and (2s2p4)4P states of atomic nitrogen by near-threshold electron impact

Abstract

Using a modified trapped-electron technique in a crossed-beam geometry, the authors have measured the total relative cross sections for electron impact excitation of the (2s22p23s)4P and (2s2p4)4P states of atomic nitrogen in the region near threshold. The (2s22P23s)4P cross section exhibits a sharp resonance at threshold, within their resolution of about 100 meV, and decreases to half the peak value 0.45 eV above threshold. The cross section for the (2s2p4)4P state increases monotonically from threshold in agreement with theory. The significance of their results to recent in situ measurements of 1200 AA and 1134 AA emission in the airglow is discussed.