The electron-impact dissociation of N2 to form two nitrogen atoms is observed in a crossed beam experiment at electron energies between 18.5 and 148.5 eV. Detection the correlated fragments with time position sensitive detector permits detection both ground excited state fragments, but excludes interference from dissociative ionization products. translational energy releases are consistent predissociation N(2D)+N(4S) as primary mechanism. Absolute cross sections for impact measured compared...

Photofragment energy distributions have been measured for the process Ar+2(2Σ+u)+hν→Ar++Ar using a 3 keV ion beam and cw lasers both coaxial crossed with beam, polarized, respectively, perpendicular parallel to direction. Measurements were made at 14 wavelengths between 4579 7993 Å. Transitions dissociative states 2Πg 2Σ+g are observed, as effects of spin–orbit interaction in Ar+2. The experimental results used along theoretical calculations determine 2Σ+u, 2Σ+g, potentials. on potential...

The electron-impact dissociation of O2 to form two oxygen atoms is observed in a crossed beam experiment at electron energies between 13.5 and 198.5 eV. Detection the correlated fragments with time position sensitive detector permits detection both ground excited state fragments, but excludes interference from dissociative ionization products. translational energy releases are consistent production O(1D)+O(3P) following impact excitation B 3Σu−, B′ 2 3Πu states, O(3P)+O(3P) (unresolved) c...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTOxygen spectroscopy below 5.1 eVT. G. Slanger and P. C. CosbyCite this: J. Phys. Chem. 1988, 92, 2, 267–282Publication Date (Print):January 1, 1988Publication History Published online1 May 2002Published inissue 1 January 1988https://pubs.acs.org/doi/10.1021/j100313a008https://doi.org/10.1021/j100313a008research-articleACS PublicationsRequest reuse permissionsArticle Views419Altmetric-Citations119LEARN ABOUT THESE METRICSArticle Views are the...

${\mathrm{N}}_{2}^{2+}$ ions, produced by electron impact of ${\mathrm{N}}_{2}$, are observed to predissociate into ${\mathrm{N}}^{+}$+${\mathrm{N}}^{+}$ when irradiated a dye laser at photon energies between 14900 and 19500 ${\mathrm{cm}}^{\ensuremath{-}1}$. Five structured bands in the spectrum associated with absorptions from $X^{1}\ensuremath{\Sigma}_{g}^{+}$ ($v=0,1,2$) three predissociated levels $1^{1}\ensuremath{\Pi}_{u}$ state. The two highest believed dissociate tunneling through...

An apparatus has been constructed to provide laser excitation of ion beams in both coaxial and crossed configurations. The geometry provides very high sensitivity nearly Doppler-free wavelength resolution for spectroscopic measurements, allows the use Doppler shift ’’tune’’ wavelength. A novel transverse quadrupole electric field arrangement is used deflect beam into out axis. highly collimated a high-resolution 180° electrostatic analyzer photofragment energy analysis. demonstrated better...

Rotationally quasibound levels (shape resonances) in the $A^{1}\ensuremath{\Pi}$ state of C${\mathrm{H}}^{+}$ are investigated with use a coaxial fast-ion-beam --- laser photofragment spectrometer. Individual shape-resonance excited radiation from high rotational $X^{1}\ensuremath{\Sigma}^{+}$ ground C${\mathrm{H}}^{+}$. The dissociative decay into ${\mathrm{C}}^{+}(^{2}P)+\mathrm{H}(^{2}S)$ is monitored by observation charged and measurement its kinetic energy. Analysis excitation...

Charge-transfer cross sections are measured for the O2+–O2 and NO+–NO systems compared with those calculated from a theoretical multistate impact parameter model which resulting coupled first-order differential equations solved numerically. Convergence in total is achieved by systematic introduction of as many 54 product states to wavefunction expansion system. At high kinetic energies (∼2 keV) computed controlled predominantly magnitude vibrational overlaps between reactant states,...

The effect of reactant-ion vibrational energy on total charge-transfer cross sections has been examined for 0.03–2.20 keV N2+–N2 and CO+–CO collisions. A multistate impact parameter treatment was applied to the examination charge transfer between above ions occupying various levels ground-state neutral molecules. resulting first-order coupled equations were solved numerically, convergence calculated achieved by systematic introduction additional states wavefunction expansion system. weighted...

Total photodestruction cross sections for O−2, O−3, and O−4 ions have been measured over a photon energy range of 1.93–2.71 eV using drift tube mass spectrometer coupled with an argon ion laser tunable dye laser. The O−2 is found to photodetach at these energies section which varies from 1.2 2.2×10−18 cm2. O−3 photodissociates form O− this 0.1 7.3×10−18 cm2 exhibits structure indicative the vibrational levels predissociating excited state. Structure also observed in 1.0 cm2, photodetachment section.

Total photodestruction cross sections for O2−, O3−, O4−, O2−⋅H2O, CO4−, CO3−, and CO3−⋅H2O have been measured over the range from 6950 to 4579 Å (1.78–2.71 eV). In most cases of these ions can be attributed specific photodissociation or photodetachment processes. The HCO3− HCO3−⋅H2O also investigated, upper limits determined their total photodestruction. experiments were performed using a drift tube mass spectrometer coupled with an argon ion laser tunable dye laser. section values vary...

The electron-impact dissociation of CO to form C and O atoms is observed in a crossed beam experiment at electron energies between the threshold (14 eV) 198.5 eV. center-of-mass energy released individual molecules explicitly measured using position time sensitive detector for correlated neutral fragments. release distribution found be highly structured, reflecting excitation Rydberg states converging CO+(X 2Σ+) which predissociate ground state atoms. Little or no from above first ionization...

We have studied the dissociative recombination of first three vibrational levels O(2) (+) in its electronic ground X (2)Pi(g) state. Absolute rate coefficients, cross sections, quantum yields and branching fractions been determined a merged-beam experiment heavy-ion storage ring, CRYRING, employing fragment imaging for reaction dynamics. present absolute total coefficients as function collision energies up to 0.4 eV five different populations ion beam, well partial (vibrationally resolved)...

This study summarizes the use of a large catalog astronomical sky spectra to different aspects OH spectroscopy and chemistry in terrestrial night sky. The are unique that they have high spectral resolution, cover entire visible wavelength region one exposure, intensity-calibrated with respect standard stars. intensity calibration, particular, allows significant revision Meinel band distribution has been for 43~years permits critical evaluation many available sets emission coefficients....

A drift tube mass spectrometer and an argon ion laser have been used to study photon interactions with CO−3, CO−3⋅H2O, HCO−3, HCO−3⋅H2O at discrete energies between 2.35 2.71 eV. CO−3 photodissociates into CO2+O− a cross section which varies 0.3 1.0×10−18 cm2 over this energy range. CO−3⋅H2O CO−3+H2O near 2×10−18 cm2. HCO−3 very small (and possibly zero) sections for photodestruction on

Absolute cross sections for the photodestruction of Cl2−, ClO−, Cl3−, and BrCl2− were measured over wavelength range 3500–7600 Å using a drift tube mass spectrometer–laser apparatus. The photodissociation section Cl2− has two bands, as been observed isoelectronic Ar2+ ion. dependence these bands is used to adjust calculated potential curves ion in Franck–Condon region. ClO− narrow band peaked at 4300 with width 400 Å, superimposed on continuum that slowly increases photon energy. attributed...

The photodissociation cross section of gas-phase CO3 − has been measured over the wavelength range from 4579 to 6940 Å, and reveals detailed structure reflecting vibrational spacings a predissociating excited electronic state. From an analysis structure, we identified three modes state having energies 990, 1470, 880 cm−1. bond energy D (CO2–O−) ground CO3− was determined be 1.8±0.1 eV, electron affinity found 2.9±0.3 eV. By comparison with theoretical calculations, lowest as 1 2A1....

Inelastic energy losses in the collisions of O+ and O2+ ions with neutral molecules have been studied a beam apparatus designed to direct mass-analyzed low-energy ion beams onto target scan energy, mass, angular distributions charged reaction products. Maxima scattered intensities are observed O+–O2 O2+–Ar systems which energetically displaced from centroids elastically by amounts corresponding known vibrational spacings respective diatomic species. Vibrational transition probabilities...

Green line emission at 557.7 nanometers arising from the O( 1 S − D) transition of atomic oxygen has been observed on nightside Venus with HIRES, echelle spectrograph W. M. Keck I 10-meter telescope. We also observe optical emissions molecular oxygen, consistent spectra Venera orbiters, but our green intensity is so high that we cannot explain how it could be inconspicuous in spectra. An upper limit for D 3 P) red 630 obtained. The large green/red ratio indicates source not associated...

Predissociation in several singlet valence and Rydberg states of molecular nitrogen has been investigated using photofragment spectroscopy. We report here measurements the yields atomic fragment products N(4S0), N(2D0), N(2P0) from predissociation specific rotational levels b′ 1Σu+ (v=9–13), c′ (v=3,4), c 1Πu o (v=3) N2. These are prepared by laser excitation metastable a″ 1Σg+ (v=0) level a fast (3 keV) beam. Correlated fragments single dissociation events monitored position- time-sensitive...

A measurement of the N(2D0) and N(2P0) yields in predissociation e 1Πu, e′ 1Σ+u, b′ 1Σ+u states molecular nitrogen is reported using photofragment spectroscopy. These are prepared by laser excitation from long-lived a″ 1Σ+g (v=0) level a fast beam. position- time-sensitive detector used to monitor two correlated fragments produced single dissociation events. The translational energy imparted establishes electronic resulting atoms hence branching among available limits nitrogen. Extremely...

The atlas of terrestrial nightglow emission lines from spectra the night sky obtained Ultraviolet and Visual Echelle Spectrograph (UVES) on 8.2‐m UT2 telescope at Very Large Telescope (VLT), European Southern Observatory, Cerro Paranal, Chile, consists 2808 line positions, widths, intensities over 314–1043 nm spectral range (Hanuschik, 2003). These have been absolute intensity calibrated measured a resolution ( λ /Δ ) ∼43,000–45,000. Presented here are spectroscopic identifications for 98%...

We report the first observation of photodissociation ${\mathrm{H}}_{3}$. Predissociation optically prepared ${3s}^{2}{A}_{1}^{\ensuremath{'}}$ and ${3d}^{2}{E}^{\ensuremath{'}\ensuremath{'}}$ states by ${\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{X}}^{2}{E}^{\ensuremath{'}}$ ground state is detected monitoring production rovibrationally excited ${\mathrm{H}}_{2}$ molecules H atoms. Product excitation found to be highly dependent on ${\mathrm{H}}_{3}$ electronic nuclear configuration.

A fast ion beam coaxial with a single mode laser has been used to measure the absorption linewidths of predissociated levels O+2(b4Σg−, v=3,4,5) by detection O+ photofragments. Tuning wavelength was accomplished combination intracavity etalons and variation velocity (Doppler tuning). Lifetimes were determined for b state fine structure rotational N=31 33 16O2+(v=3), N=9–25 16O2+(v=4), N=14–27 16,18O2+(v=4), N=5–7 16O2+(v=5). The lifetimes vary from 0.06 4 nsec. Variation all relevant quantum...