Excited hydrogen and argon atom production by charge transfer of metastable Ar+ ions in H2 molecules

Rothwell, H. L.; Amme, Robert C.; Zyl, B. Van

doi:10.1063/1.436268

Cited by 14 publications

(8 citation statements)

References 4 publications

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“…This is not in conflict with the work of Rothwell et al [6], since that measurement was made at an energy below the threshold of reaction (5). In any case, in [-6] only overall formation of metastable neutral Ar was detected irrespective of any simultaneous production of H(n=2).…”

Section: Resultsmentioning

confidence: 80%

“…In spite of the differences of ion source conditions (discharge through ~0.1 torr of Ar in the present work, versus low-pressure electron impact excitation in Hagstrum's), good agreement in the overall curve shape is obtained. Rothwell et al [6], too, found an onset of L~ production at about 32 eV electron energy, which is the appearance potential of the Ar+(4D7/2) metastable component. Thus Fig.…”

Section: Resultsmentioning

confidence: 95%

“…Rothwell et al [6] have studied this process at the fixed energy of 6 eVcM and give an absolute cross section of 4.8 x l0 -t6 cm 2. This is again based on…”

Section: Resultsmentioning

confidence: 99%

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L ? emission from Ar++H2 collisions in the threshold energy region

Ottinger¹,

Yang²

1985

Z Physik A

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In the energy range 2.4 to 33.3 eVcra, relative cross sections have been measured for L~ emission from impact of Ar § ions in a beam on a H 2 gas target. Absolute cross sections, obtained by normalization to literature data, are 1-10 x 10 -16 cm 2 for metastable Ar § and 1-20x10-18cm 2 for ground state Ar § In the former case, the dominant mechanism is probably dissociative electronic energy transfer, while in the latter case dissociative charge transfer is the most likely process. In addition,~at the lowest energies L~ resulting from a chemiluminescent rearrangement Ar++ H 2--, ArH + +H(2p) has been observed.

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Section: Resultsmentioning

confidence: 80%

Section: Resultsmentioning

confidence: 95%

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L ? emission from Ar++H2 collisions in the threshold energy region

Ottinger¹,

Yang²

1985

Z Physik A

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“…In brief, a tunable diode laser (TLB-6900 VortexTM II; New Focus, Santa Clara, CA, USA) with a nominal wavelength of 1083 nm was used to excite three transitions between 1082.85 and 1083. 15 states. An InGaAs photodiode (SM05PD5A; ThorLabs, Newton, NJ, USA) was used as the detector.…”

Section: Atomic Absorption Measurements Of Helium Metastable Atomsmentioning

confidence: 99%

“…There is good reason to think that adding hydrogen to argon could improve its performance as an ADI plasma gas. The effects of hydrogen on argon plasmas have been studied extensively by researchers in the field of inductively coupled plasma mass spectrometry (ICP-MS) [11][12][13][14][15]. Hydrogen has been found to be an effective way to remove argon ions from the ion beam in ICP-MS.…”

Section: Introductionmentioning

confidence: 99%

The Effects of Added Hydrogen on Noble Gas Discharges Used as Ambient Desorption/Ionization Sources for Mass Spectrometry

Ellis

Lewis

Openshaw

et al. 2016

J. Am. Soc. Mass Spectrom.

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Abstract. We demonstrate the effectiveness of using hydrogen-doped argon as the support gas for the dielectric barrier discharge (DBD) ambient desorption/ionization (ADI) source in mass spectrometry. Also, we explore the chemistry responsible for the signal enhancement observed when using both hydrogen-doped argon and hydrogen-doped helium. The hydrogen-doped argon was tested for five analytes representing different classes of molecules. Addition of hydrogen to the argon plasma gas enhanced signals for gas-phase analytes and for analytes coated onto glass slides in positive and negative ion mode. The enhancements ranged from factors of 4 to 5 for gas-phase analytes and factors of 2 to 40 for coated slides. There was no significant increase in the background. The limit of detection for caffeine was lowered by a factor of 79 using H 2 /Ar and 2 using H 2 /He. Results are shown that help explain the fundamental differences between the pure-gas discharges and those that are hydrogen-doped for both argon and helium. Experiments with different discharge geometries and grounding schemes indicate that observed signal enhancements are strongly dependent on discharge configuration.

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L ? emission from collisional excitation of H Atoms by threshold energy Ar+ ions

Müller¹,

Ottinger²,

Yang³

1985

Z Physik A

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In a specially designed collision chamber, H atoms produced by a microwave discharge were excited into the 2p state by impact of Ar + ions in a beam. A degree of dissociation up to t/= 94 % was measured at the exit of the microwave source, although in the center of the collision cell ~ is smaller, with a lower limit of 33 %. The effect of vibrational excitation of H 2 by the discharge and the resulting difficulties of measuring t/ are discussed. The cross section for L= emission increases linearly from the threshold, at 10.2 eVcM, to 17.1 eVcM. The absolute cross section at this energy is 1.5.10 -17 cm 2 for r/=33% (with a minimum of 0.6.10-17 cm 2, for the maximum possible t/). The absence of an activation barrier rules out some features shown by an earlier ab initio calculation.

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Excited hydrogen and argon atom production by charge transfer of metastable Ar+ ions in H2 molecules

Cited by 14 publications

References 4 publications

L ? emission from Ar++H2 collisions in the threshold energy region

L ? emission from Ar++H2 collisions in the threshold energy region

The Effects of Added Hydrogen on Noble Gas Discharges Used as Ambient Desorption/Ionization Sources for Mass Spectrometry

L ? emission from collisional excitation of H Atoms by threshold energy Ar+ ions

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