Electron Excitation Function of the N 2 Second Positive System

Abstract

view Abstract Citations (36) References (30) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Electron Excitation Function of the N 2 Second Positive System Shemansky, D. E. ; Ajello, J. M. ; Kanik, I. Abstract The band strengths of the electron excited N2 (C 3Πu-B 3Πg) second positive system (2PG) have been measured in the middle ultraviolet (MUV) range (280-444 nm). The energy dependence of the (0,0) and (1,0) band cross sections is reported with analytic shape functions for use in model calculations. The excitation functions were measured at low pressure to avoid effects of collisional cascade from higher lying states. At low electron energies (11-15 eV), the resolution and energy spacing of the excitation function measurements were sufficient to reveal the importance of threshold effects from resonance processes. The absolute cross section of the 337.14 nm band has a peak value of 1.11±0.15 × 10-17 cm2 at 14.1 eV. Above 30 eV the cross section decreases with an asymptotic E-2 dependence. A spectral analysis of the 2PG band system at 14 and 20 eV has provided relative excited state vibrational level cross sections. The variation of the electronic transition moment over the wavelength range indicated above, has been derived, and an improved transition probability matrix has been obtained. The rate coefficient for solar photoelectron excitation of the (0,0) band is 9.1 × 10-10 cm-3 s-1 for photoelectrons above 11.0 eV, a factor of ∼1.3 smaller than the previous recommended value. Publication: The Astrophysical Journal Pub Date: October 1995 DOI: 10.1086/176319 Bibcode: 1995ApJ...452..472S Keywords: ATMOSPHERIC EFFECTS; EARTH; MOLECULAR DATA; ULTRAVIOLET: GENERAL full text sources ADS |