Luminescence measurements of hyperthermal Xe2++ O2and O++ Xe collision systems

Hause, Michael L.; Solter, Sierra; Prince, Benjamin D.; Bemish, Raymond J.

doi:10.1039/c9cp05314j

Cited by 1 publication

(2 citation statements)

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“…Experimental measurements were made in an ion beam luminescence apparatus described previously , and modified to obtain fast neutral–molecule reactions, similar to the experiments of Ottinger and Kowalski . As in our recent Xe 2+ + O 2 experiment, the ion beam of interest is first generated in a radio frequency (RF) ion source (RFIS-100, Beam Imaging Systems). Xenon and krypton singly charged ions were generated from research grade gases (Advanced Specialty Gases) with source pressures of about 100 mTorr and RF wattage between 60 and 100 W. For N + , about 30–40 mTorr of krypton gas was used in the source as a seed gas.…”

Section: Methodsmentioning

confidence: 99%

“…Detection time and luminescence occurring outside of the collision cell was not explicitly included but will be compared to He + + ND 3 experiments by Drozdowski et al in section . A tool, previously described, , was used to sample basis sets with different rotational temperatures to find the best fit. A single rotational temperature was used to estimate all bands as the spectral resolution did not allow separation of rotational structure.…”

Section: Methodsmentioning

confidence: 99%

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Luminescence Measurements of the Hyperthermal Reactions of N/N⁺ + NH₃

Hause¹,

Prince²,

Bemish³

2023

J. Phys. Chem. A

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Chemiluminescence from a system of collisions, N + / N/Kr + /Kr/Xe + /Xe + NH 3 , at collision energies between 10 and 170 eV (center of mass, COM), was measured in the spectral range 300−1000 nm. The energy dependence of the emission excitation cross sections was quantified, and molecular signatures were fit to known spectroscopic constants to determine vibrational-state populations. For both N and N + collision species, the strongest features were assigned to emissions from NH (A−X) and the atomic hydrogen Balmer series. For each of the spectra resulting from collisions with primary cations, the NH (A−X) emissions had the largest cross sections reaching values of (1.0−1.5) × 10 −18 cm 2 by 100 eV. Additional features originating from atomic nitrogen and NH (c−a) emissions were also observed. The NH (c−a) emissions accounted for about 8%, 13%, and 15% for total excited populations in collisions with Xe + , N + , and Kr + , respectively. These transitions were consistent with short-range interactions resulting in collision-induced dissociation of the NH 3 molecule with apparent energy thresholds between 20 and 30 eV and emission cross sections decreasing with ion mass. Evidence of charge exchange in the N + + NH 3 collisions was observed in the resulting spectra as broad transitions between 420 and 480 nm and were assigned to NH + emitting from the (B) state. Differences between the spectra were observed as changes in the emission signal with the neutral collisions producing only 30% or 65% of the NH (A−X) emission cross sections compared to the cation results for xenon and krypton, respectively. For N and N + , NH (A) was created in equal amounts at lower collision energies, but the emission for the neutral system increases above that of the cation at collision energies greater than 80 eV COM. In both cases, the threshold energy for appearance was below 10 eV, suggesting an additional pathway for NH (A) formation, namely, hydrogen abstraction or charge exchange and abstraction for the N and N + , respectively. In all cases, the neutral NH (c−a) emission intensity was similar between neutral and cation pairs. The H-α emission line (n = 3−2) decreased to about 10%, 33%, and 50% of the corresponding cation spectra for xenon, krypton, and nitrogen, respectively.

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