Monomolecular and collision-induced predissociation in the mass spectrum of DBr

Mathieu, G.; Wankenne, H.; Momigny, J.

doi:10.1016/0009-2614(72)87069-6

Cited by 11 publications

(3 citation statements)

References 8 publications

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“…These rules have recently been revised in cases where spin-orbit coupling has to be considered [21]. Predissociations of diatomic molecular ions with life-times of the order of 10 -6 s have been observed in sectorfield mass spectrometers as "metastable" peaks characterized by their shape, width and position at fractional mass numbers [19][20][21].…”

Section: Dissociative Ionization Processesmentioning

confidence: 99%

The dissociative ionization in oxygen

Locht

Schopman

1974

International Journal of Mass Spectrometry and Ion Physics

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Section: Dissociative Ionization Processesmentioning

confidence: 99%

The dissociative ionization in oxygen

Locht

Schopman

1974

International Journal of Mass Spectrometry and Ion Physics

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“…One of the dissociation channels a molecule can choose is the predissociation observed in several neutral and ionized species. Besides the optical spectroscopy methods, predissociations have been investigated by a variety of techniques such as "metastable ion" mass spectrometry [1,2], high resolution translational spectroscopy [3,4] as well as photoelectron spectroscopy [5,6].…”

Section: Introductionmentioning

confidence: 99%

“…If only molecular ion states are considered in this energy range, the 2 However, taking into account the selection rule for non-radiative transitions [18], related to the symmetry of the repulsive states which could be involved, the predissociation of the 2 Φ u state is strong-ly forbidden. Considering the potential energy curves given by Gilmore [17], only the 2 Σ g + , the 4 Σ g + and the 4 Π g state could predissociate the 2 Φ u state.…”

mentioning

confidence: 99%

The observation of predissociations in the oxygen molecular ion by low-energy electron impact

Schopman

Locht

1974

Chemical Physics Letters

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The kinetic energy distribution of the O + ions formed by dissociative ionization of O2 has been carefully ex-amined in the range of 0.0 to 1.3 eV. In the peak at 600 meV fine structure is observed and interpreted by predissociation. The high energy side of the peak has been ascribed to the predissociation of the 2 ∆ g , B 2 Σ g -and the c 4 Σ u -states of O 2 + . The low energy side of the peak is presumably due to the predissociation of the b 4 Σ g -state or the Φ u state of O 2 + or to autoionizing predissociation.During the last few years much attention has been paid to the dissociation of diatomic molecules. One of the dissociation channels a molecule can choose is the predissociation observed in several neutral and ionized species. Besides the optical spectroscopy methods, predissociations have been investigated by a variety of techniques such as "metastable ion" mass spectrometry [1,2], high resolution translational spectroscopy [3,4] as well as photoelectron spectroscopy [5,6].The dissociation of the oxygen molecular ion has been the subject of several papers. Doolittle et al. [7] obtained the kinetic energy distribution curve of O + from O 2 by using photoionization mass spectrometry. Freund [8] and Kieffer et al. [9] studied the kinetic energy carried away by the 0 ions formed by electron impact on O 2 . These authors ascribed the first broad and structureless peak, with a maximum at 850 meV, to O + fragment ions formed by predissociation, although no direct experimental evidence was found for this mechanism. Recently Danby and Eland [5] showed experimentally the existence of a predissociation of O 2 by using the photoelectronphotoion coincidence technique.The purpose of this paper is to report our results obtained for the kinetic energy analysis of the O + ions formed by electron impact on molecular oxygen;The instrument used, as well as the experimental conditions will be described elsewhere [10]. Briefly, the ions formed in a conventional Nier-type ion source pass through a retarding potential system before entering into a quadrupole mass spectrometer. The ion current is, at fixed electron energy, continuously scanned with respect to the retarding potential or with respect to electron energy at fixed retarding potential. The first derivative of either the retarding curves or the ionization efficiency curves is stored in a multichannel analyser and plotted on an X-Y recorder.A preliminary report [11] has been devoted to the kinetic energy distribution curve of O + from O 2 , spread over a broad energy range (0 to 12 eV). These results will be published elsewhere [10]. In this letter we will limit our discussion to the results obtained in the energy range of 0 to 1.3 eV.An example of a kinetic energy distribution of O + from O 2 , as observed by the impact of 25 eV electrons, is shown in fig. 1.The first peak maximum is measured at 0.0 eV coinciding with the maximum of the thermal distribution of the molecular ion O 2 , taken as the origin of the kinetic energy scale. The second maximum, meas...

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Low Rate Fragmentation Reactions of Gaseous Ions

Ferreira¹

1984

Ionic Processes in the Gas Phase

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Monomolecular and collision-induced predissociation in the mass spectrum of DBr

Cited by 11 publications

References 8 publications

The dissociative ionization in oxygen

The dissociative ionization in oxygen

The observation of predissociations in the oxygen molecular ion by low-energy electron impact

Low Rate Fragmentation Reactions of Gaseous Ions

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