Electron-capture cross sections of multiply charged slow ions of carbon, nitrogen, and oxygen in He

Ishii, K.; Itoh, Akio; Okuno, K.

doi:10.1103/physreva.70.042716

Cited by 37 publications

(45 citation statements)

References 41 publications

(61 reference statements)

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“…3 together with other available measurements and MCLZ calculations. For O 3+ -He collisions, our results are in reasonably good agreement with the experimental results of Bangsgaard et al [6] and Ishii et al [9] and show similar behavior, However, our data are considerably higher than the recommended cross sections of Janev et al [10] and found to be 60% higher than the multi-channel Landau-Zener calculations [6], based on the Taulberg expression for the coupling matrix H 12 [11]. For O 3+ + H 2 O and CO 2 collisions, the total cross sections exhibit weak energy dependence and they are almost constant with increasing impact energy, a behavior that is attributed to availability of many reaction channels that are situated nearly at the center of the reaction window.…”

Section: Total Cross Sectionssupporting

confidence: 82%

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Electron capture by O³⁺ions from He, H₂O and CO₂

Abu-Haija¹,

Wardwell²

2007

J. Phys.: Conf. Ser.

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Abstract. Using the translational energy-gain spectroscopy technique, we have measured the energy-gain spectra and absolute total cross sections for single - IntroductionThe study of electron capture processes in collisions of multiply-charged ions with molecular targets has recently received considerable theoretical and experimental attention. A number of mechanisms have been suggested for the charge balance of astrophysical plasmas and the origin of the x-ray emission from comets and planetary atmospheres. One of those is the electron capture mechanism between multiply charged ions present in the solar wind and atmospheric and cometary gases. Electron capture processes can also significantly affect the thermal and ionization structure of a wide variety of astrophysical plasmas. Data for electron capture are therefore essential to the understanding and interpretation of the O + and O 2+ emission lines in interstellar medium [1, 2]. Translational energy spectroscopy has been extensively used to study state-selective electron capture by multiply-charged oxygen ions from rare-gas atoms and atomic and molecular hydrogen. However in case of H 2 O and CO 2 targets, there have been no previous experimental measurements of cross sections, differential in translational energy-gain and projectile scattering angle, for stateselective electron capture at low energies.In the present work, a differential energy-gain spectrometer [3], capable of measuring simultaneously the scattering angle and the energy-gain of projectile products in ion-atom collisions, has been used for the study of state-selective single-electron capture in collisions of O 3+ recoil ions with He, H 2 O and CO 2 at impact energies between 0.3 and 1.2 keV and scattering angles between 0

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Section: Total Cross Sectionssupporting

confidence: 82%

“…For O 3+ + CO 2 collisions, The MCLZ results are at least a factor of 2 smaller than the experimental results and show the same energy dependence. , present work; , Ishii et al [9]; , Bangsgaard et al [6]; , Janev et al [10]; solid line, MCLZ calculations.…”

Section: Total Cross Sectionsmentioning

confidence: 99%

Electron capture by O³⁺ions from He, H₂O and CO₂

Abu-Haija¹,

Wardwell²

2007

J. Phys.: Conf. Ser.

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“…Slow and Fast Solar Wind Parameters. Cross sections for CX between SW heavy ions and H and He are based on theoretical and experimental work of (Beijers et al 1994;Bliman et al 1992;Bonnet et al 1985;Dijkkamp et al 1985a,b;Fritsch et al 1996;Greenwood et al 2001;Harel et al 1992Harel et al , 1998Ishii et al 2004;Iwai et al 1982;Lee et al 2004;Liu et al 2005;Phaneuf et al 1987;Richter et al 1993;Shimakura et al 1992;Suraud et al 1991;Wu et al 1994 work is, however, certainly needed to improve the accuracy of the helium ionization rate of helium ).…”

Section: Hydrogen and Helium Density Gridsmentioning

confidence: 99%

Charge-transfer induced EUV and soft X-ray emissions in the heliosphere

Koutroumpa¹,

Lallement²,

Kharchenko

et al. 2006

A&A

105

170

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Aims. We study the EUV/soft X-ray emission generated by charge transfer between solar wind heavy ions and interstellar neutral atoms and variations of the X-ray intensities and spectra with the line of sight direction, the observer location, the solar cycle phase and the solar wind anisotropies, and a temporary enhancement of the solar wind similar to the event observed by Snowden et al. (2004) during the XMM-Hubble Deep Field North exposure. Methods. Using recent observations of the neutral atoms combined with updated cross-sections and cascading photon spectra we have computed self-consistent distributions of interstellar hydrogen, helium and highly charged solar wind ions for a stationary solar wind and we have constructed monochromatic emission maps and spectra. We have evaluated separately the contribution of the heliosheath and heliotail, and included X-ray emission of the excited solar wind ions produced in sequential collisions to the signal. Results. In most practicable observations, the low and medium latitude X-ray emission is significantly higher at minimum activity than at maximum, especially around December. This occurs due to a strong depletion of neutrals during the high activity phase, which is not compensated by an increase of the solar wind flux. For high latitudes the emission depends on the ion species in a complex way. Intensity maps are in general significantly different for observations separated by six-month intervals. Secondary ions are found to make a negligible contribution to the X-ray line of sight intensities, because their density becomes significant only at large distances. The contribution of the heliosheath-heliotail is always smaller than 5%. We can reproduce both the intensity range and the temporal variation of the XMM-HDFN emission lines in the 0.52-0.75 keV interval, using a simple enhanced solar wind spiral stream. This suggests a dominant heliospheric origin for these lines, before, during and also after the event.

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“…A consequence of the electron capture process having a comparatively large collision cross-section [29] is that low intensity charge reduction peaks are frequently seen at the very low flight tube pressures used to study unimolecular decay. Evidence of this is seen in Figure 2b where residual electron capture peaks are present at laboratory-frame kinetic energies Ͼ5000 eV.…”

Section: Mike Spectra: Unimolecular and Collision-induced Dissociatiomentioning

confidence: 99%

“…Overall stability of a fully solvated metal ion may depend on the formation of an extended network of hydrogen bonds [29], and that is more easily achieved when water (up to 8 H-bonds) rather than methanol (up to 4 H-bonds) forms a four-coordinate primary solvation shell. However, much also depends on how effective structures are at using charged enhanced hydrogen bonds to lock molecules into configurations that provide more limited access to the primary shell.…”

Section: Bond Length Comparisonsmentioning

confidence: 99%

A Gas-phase study of the preferential solvation of Mn²⁺ in mixed water/methanol clusters

Duncombe

Rydén

Puškar

et al. 2008

J. Am. Soc. Mass Spectrom.

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The kinetic shift that exists between two competing unimolecular fragmentation processes has been used to establish whether or not gas-phase Mn 2ϩ exhibits preferential solvation when forming mixed clusters with water and methanol. Supported by molecular orbital calculations, these first results for a metal dication demonstrate that Mn 2ϩ prefers to be solvated by methanol in the primary solvation shell. (J Am Soc Mass Spectrom 2008, 19, 520 -530 [4 -9], but equally important is behavior in many-component solvents, where competing interactions may be dominated by differences in molecular properties [10 -12]. In general, a condensed phase solution containing solvents with very similar pure-state properties might be expected to behave in a manner that reflects the composition of the solvent mixture [13]. There have been several attempts to simulate the behavior of metal dications in mixed solvent systems, [14 -18], and of particular significance to the work discussed here are the molecular dynamics studies of Day and Patey [14,15]. From simulations of an ion in the presence of water and methanol they concluded that a positively charged solute exhibits a pronounced preference for water. If there are large differences in the solvating abilities of the components, selective or preferential solvation may occur [11,12]; however, the degree of averaging present in a typical condensed phase system means that subtle effects due to small differences in free energy are unlikely to make their presence felt [13]. In contrast, the consequences of small, individual differences in molecular properties can be amplified in the gas phase because of the influence they may have on establishing equilibria or determining fragmentation pathways [10, 19 -21]. Presented here are the results of a study designed to see if an established technique for generating multiply charged metal/solvent complexes in the gas phase can yield useful information on behavior in mixed solvent systems. From this first study, the experimental results demonstrate that for water and methanol as solvents, gas-phase Mn 2ϩ does exhibit preferential solvation. This conclusion is supported by detailed molecular orbital calculations on a wide range of mixed [Mn(MeOH) 2ϩ complexes, which show that small differences in the binding energies of methanol and water are sufficient to account for the experimental results. ExperimentalThe experimental apparatus used for the generation and detection of gas-phase multiply charged metalligand complexes has been described extensively in previous publications [22]. Briefly, mixed neutral argon/ligand clusters are produced by the adiabatic expansion of solvent vapor mixed with argon through a pulsed supersonic nozzle. Previous work on the preferential solvation of hydrogen ions in clusters composed of methanol and water showed that the composition of ionized clusters depended quite significantly on the composition of the coexpansion mixture [19]. In this study, several mixtures were evaluated, but it was found that a ratio of 5:1,...

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Electron-capture cross sections of multiply charged slow ions of carbon, nitrogen, and oxygen in He

Cited by 37 publications

References 41 publications

Electron capture by O³⁺ions from He, H₂O and CO₂

Electron capture by O³⁺ions from He, H₂O and CO₂

Charge-transfer induced EUV and soft X-ray emissions in the heliosphere

A Gas-phase study of the preferential solvation of Mn²⁺ in mixed water/methanol clusters

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Electron-capture cross sections of multiply charged slow ions of carbon, nitrogen, and oxygen in He

Cited by 37 publications

References 41 publications

Electron capture by O3+ions from He, H2O and CO2

Electron capture by O3+ions from He, H2O and CO2

Charge-transfer induced EUV and soft X-ray emissions in the heliosphere

A Gas-phase study of the preferential solvation of Mn2+ in mixed water/methanol clusters

Contact Info

Product

Resources

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Electron capture by O³⁺ions from He, H₂O and CO₂

Electron capture by O³⁺ions from He, H₂O and CO₂

A Gas-phase study of the preferential solvation of Mn²⁺ in mixed water/methanol clusters