HIGH-RESOLUTION ELECTRON-IMPACT EMISSION SPECTRA AND VIBRATIONAL EMISSION CROSS SECTIONS FROM 330–1100 nm FOR N₂

Abstract

Electron-impact emission cross sections for N2 were measured in the wavelength range of 330–1100 nm at 25 eV and 100 eV impact energies. Cross sections of several molecular emission bands of the first positive band system B 3Π g +(ν′) → A 3Σ g +(ν″) and the second positive band system C 3Π u (ν′) → B 3Π g (ν″) of N2, the first negative band (1NB) system B 2Σ u +(ν′) → X 2Σ g +(ν″) and Meinel band system A 2Π u (ν′) → X 2Σ g +(ν″) of N2 + ions as well as line emissions of N (N i) and N+ (N ii) in the visible–optical–near-IR wavelength range reported in this work were measured for the first time in a single experimental setup at high spectral resolving power (λ/Δλ ≈ 10000) under single-collision-scattering geometry and optically thin conditions. Rotational emission lines of N2 and N2 + were observed for strong emission bands at a gas temperature of about 300 K. The absolute cross section of the strongest (0,0) vibrational band at 391.43 nm of 1NB was determined using the standard Hα emission cross sections of H2 by electron impact at both 25 eV and 100 eV electron-impact energies, and the cross sections for the remainder of the emissions were determined using (0,0) 1NB value. A comparison of the present emission cross sections with the earlier published data from both electron energy loss and electron-impact-induced fluorescence emission is discussed.

THE HIGH-RESOLUTION EXTREME-ULTRAVIOLET SPECTRUM OF N 2 BY ELECTRON IMPACT

“…Further electron-induced fluorescence occurs from the Lyman-Birge-Hopfield (LBH) series of bands originating from the a 1 Π g excited state. The UV emission studies of N 2 by electron-impact-induced fluorescence carried out over the past 30 years at the Jet Propulsion Laboratory (JPL) have been motivated by both astrophysical and theoretical interest (Ajello & Shemansky 1985;Ajello et al 1989Ajello et al , 1998Ajello et al , 2007Ajello et al , 2008Ajello et al , 2011aAjello et al , 2011bAjello et al , 2012James et al 1990;Mangina et al 2011;Young et al 2010). Intense atomic emissions in the dayglow from the atmospheres of N 2 -bearing solar system objects occur mainly from solar photodissociative ionization (PDI) and in the nightglow by collision with secondary electrons and other particles (e.g., magnetospheric protons and O + ; Ajello et al 2011aAjello et al , 2011bAjello et al , 2012Cravens et al 2008Cravens et al , 2010.…”

“…The Cassini spacecraft orbiting the Saturn system is equipped with a low-resolution (λ/Δλ = 200) Ultraviolet Imaging Spectrograph (UVIS) operated in two spectral channels spanning the range from 561 to 1913 Å, and the UV-visible-near-IR Imaging Sub-System (Esposito et al 2004). The former instrument is capable of observing N 2 in the Titan airglow in the EUV and FUV, and the latter is suitable to study N 2 eclipse darkside emissions filtered into 15 band passes covering the UV-visiblenear-IR spectral range (2350-11000 Å; Ajello et al 2007Ajello et al , 2008Stevens et al 2011;Mangina et al 2011;West et al 2012).…”

Charged defects and defect‐induced processes in nitrogen films

“…The only band, free from overlap, is the band corresponding to the 0-0 transition. Its shape is characterized by strong narrow band coinciding with 0-0 term of the C 3 Π u →B 3 Π g progression in the gas phase spectrum excited by an electron beam [31]. The blue subband is close to the rotational R branch.…”

Detection limits of organic compounds achievable with intense, short-pulse lasers

“…To extend the measurements to lower intensities (∼10 12 W cm −2 ), data was also acquired with the laser focus shifted 18 mm off the ToF axis. 50 By fitting eqn (5) to the data, three photon cross sections of 1.8 × 10 −83 cm 6 s 2 and 3.5 × 10 −84 cm 6 s 2 for O 2 and N 2 were derived with an uncertainty of 40%. 1(a).…”