Electron Impact Ionization of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi>C</mml:mi></mml:mrow><mml:mrow><mml:mn>60</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>

Dünser, B.; Lezius, M.; Scheier, P.; Deutsch, Hans‐Peter; Märk, T. D.

doi:10.1103/physrevlett.74.3364

Cited by 49 publications

(45 citation statements)

References 29 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The inclusion of coupling to inelastic channels may therefore be expected to improve the performance of the SMC method at higher energies in the present case; however, two considerations argue against this view. First, the shape of the SMC DCSs for C 60 agrees quite well with the present measurements at 100 and 150 eV, in the energy range where the electron-impact ionization cross section of C 60 is maximal [33,34]. Second, the spherical-shell and independent-atom and Born models also neglect inelastic channels, yet each describes the fall-off of the DCS with angle at the higher energies better than the SMC calculation.…”

Section: Resultssupporting

confidence: 72%

Elastic scattering of intermediate-energy electrons fromC60molecules

et al. 2010

View full text Add to dashboard Cite

Experimental and calculated differential cross sections for elastic scattering of electrons by C 60 molecules at collision energies of 100 to 500 eV are reported. The elastic differential cross sections were measured in a standard crossed-beam apparatus, while the calculations were performed employing the Schwinger multichannel technique at the static-exchange level. Diffraction effects, some due to the overall spherical-cage structure and some to scattering by individual C atoms, are observed in both the measured and calculated cross sections.

show abstract

Section: Resultssupporting

confidence: 72%

Elastic scattering of intermediate-energy electrons fromC60molecules

et al. 2010

View full text Add to dashboard Cite

show abstract

“…Apparently direct vibrational excitation leads preferentially to evaporation, whereas electronic excitation is responsible for multifragmentation. In the intermediate range we find indications for a "transparency window" similar to that predicted recently in simulations of Na The interaction of fullerenes with particles such as photons [1], electrons [2], and ions [3] leads to fragmentation patterns which can serve as a fingerprint of the interaction process. Ion-fullerene (and fullerene-ion-atom) collisions have been studied for different collision systems at a variety of collision velocities and projectile charge states recently.…”

Section: Strong Velocity Effects In Collisions Ofmentioning

confidence: 50%

Strong Velocity Effects in Collisions ofHe+with Fullerenes

et al. 1999

View full text Add to dashboard Cite

We have studied fragmentation and ionization of C 60 by He 1 impact over a velocity range from 0.1 to 1 a.u. where a transition from vibrational to electronic excitation is predicted. With increasing velocity we observe a strong decrease of evaporative processes (C r1 6022m peaks) and a linearly increasing yield of small fragments ͑C 1 n , n , 15͒. Apparently direct vibrational excitation leads preferentially to evaporation, whereas electronic excitation is responsible for multifragmentation. In the intermediate range we find indications for a "transparency window" similar to that predicted recently in simulations of Na 1 9 -He collisions. [S0031-9007(98)08105-8] PACS numbers: 36.40.Qv, 34.50.Bw, 36.40.Wa, 61.48. + cThe interaction of fullerenes with particles such as photons [1], electrons [2], and ions [3] leads to fragmentation patterns which can serve as a fingerprint of the interaction process. Ion-fullerene (and fullerene-ion-atom) collisions have been studied for different collision systems at a variety of collision velocities and projectile charge states recently. In the E c.m. , 250 eV range (corresponding to a projectile velocity of ഠ0.05 a.u.; in the following, we will always use the projectile velocity to characterize the collision), collisional fragmentation is mainly due to direct vibrational excitation of the target clusters [4]; the bimodal fragment distributions show close similarities to, e.g., photofragmentation results [1], indicating an independence of the fragmentation process on the exact nature of the excitation mechanism [5]. Little is known about the excitation mechanisms in the keV range ͑y ഠ 0.1 1 a.u.͒, where the interaction times are much shorter. In this range, collisions of multiply charged ions with fullerenes have been studied with great interest [6][7][8][9]. These collisions lead to remarkable mass distributions of the collision products. On the one hand, C r1 60 clusters are formed in a gentle way [10,11], for highly charged projectiles up to r 9 [12]. On the other hand, the fragment distribution ͑C 1 n ͒ peaks at n 1, i.e., very small fragments are formed in such collisions. Similar results are observed for MeV collisions ͑y . 1 a.u.͒ of multiply charged ions with fullerenes [13][14][15]. Whereas the first finding can be explained by electron capture at large distances, without kinetic energy transfer from the projectile to the C 60 , the explanation for the occurrence of the small fragments is less obvious. Under the assumption that these fragments are due to very close collisions, one can obtain information about the mechanisms by varying the collision energy. Furthermore, a singly charged projectile is favorable for such a study to avoid potential energy effects.We investigate the transition from vibrational to electronic excitation in such close collisions experimentally for the system He 1 -C 60 in the velocity range between 0.1 and 1 a.u.For the present experiment He 1 ions are extracted from an electron cyclotron resonance source, floated on a potential between 1 and 2...

show abstract

“…8) by single electron collision in the energy range from threshold up to 1000 eV, including ions with charge states up to z = 4 and fragment ions down to C,, [30]. For these measurements we used the crossed beams apparatus described above invoking, however, for these measurements a novel technique for the absolute calibration of the cross-sections (see below).…”

Section: Absolute Partial and Total Ionization Cross-sectionsmentioning

confidence: 99%

“…It is interesting to note that the one previous calibration [65]-using a Knudsen cell approach-leads to total counting crosssections which are also larger than these geometric cross-sections. A more detailed account of the measured C,, cross-sections and also of those of C,, will be presented in [38] (see also [30]). …”

Section: Absolute Partial and Total Ionization Cross-sectionsmentioning

confidence: 99%

Electron impact ionization of C₆₀and C₇₀: production and properties of parent and fragment ions studied with a two-sector field mass spectrometer

Scheier

Dünser

Wörgötter

et al. 1996

International Reviews in Physical Chemistry

Self Cite

View full text Add to dashboard Cite

Electron impact ionization and dissociation studies of C,, and C,, carried out in our laboratory over the past three years have revealed many exciting and novel features of this new class of molecules (clusters). The most salient results are summarized in this paper, including first a description of the crossed beams apparatus and the various mass spectrometric (two-sector field) techniques used. This is followed by a discussion of the production of parent and fragment ions (with up to eight charges) via electron impact ionization of C,, and C,, including results on mass spectral fragmentation patterns and measured and calculated absolute ionization cross-section functions. The experimental results concerning the energetics of produced parent and fragment ions are presented in the next section and measured appearance energies and breakdown curves are analysed in the frame of various theoretical concepts (RRKM, FHBT) thereby allowing us to derive the corresponding binding energies. The last section is devoted to (i) the different aspects of the stability of singly-and multiply-charged fullerene ions (i.e. the quantitative study of various unimolecular decay channels such as monomer evaporation, sequential decay series, charge separation reactions, etc.) and, based on the measured properties of these decay reactions, to (ii) a discussion of the possible decay mechanisms. IntroductionSince the first report about the unique structure of C,, by Kroto et al. [l] in 1985 and the discovery by Kratschmer et al. [2] in 1990 as to how to produce gram quantities of C,, (and other fullerenes), a new world of chemistry, physics and material science has developed and is growing at a tremendous rate [3]. It is important to remember that the key original experiment which allowed the bold conclusion about the special nature of C,, (i.e. the truncated icosahedral structure) included a positive and negative carbon cluster ion mass spectrum. During the past two years we have carried out a series of mass spectrometric investigations concerning the electron impact ionization and the electron attachment of C,, and C7,. Not too surprisingly, C,, (and C,,) also exhibits in this respect, i.e. electron ionization and attachment, rather tantalizing properties-unparalleled by other molecular systems.For example, the first measurements-carried out using a crossed beams apparatus-of electron attachment cross-section functions for C,, and C,, revealed an unusually large cross-section for the production of C;, and C;, , , respectively [4]. It was observed, moreover, that only parent ions (and absolutely no fragment anions, which is in contrast to the situation encountered for ordinary molecules [5]) are produced by the attaching electrons and that the cross-section remained high (in the order of lo-'* m2) from near zero electron energy up to about 10 eV and then reduced quickly to reach zero at about 15 eV electron energy. Resonance structures observed have been

show abstract

Electron Impact Ionization ofC60

Cited by 49 publications

References 29 publications

Elastic scattering of intermediate-energy electrons fromC60molecules

Elastic scattering of intermediate-energy electrons fromC60molecules

Strong Velocity Effects in Collisions ofHe+with Fullerenes

Electron impact ionization of C₆₀and C₇₀: production and properties of parent and fragment ions studied with a two-sector field mass spectrometer

Contact Info

Product

Resources

About

Electron Impact Ionization ofC60

Cited by 49 publications

References 29 publications

Elastic scattering of intermediate-energy electrons fromC60molecules

Elastic scattering of intermediate-energy electrons fromC60molecules

Strong Velocity Effects in Collisions ofHe+with Fullerenes

Electron impact ionization of C60and C70: production and properties of parent and fragment ions studied with a two-sector field mass spectrometer

Contact Info

Product

Resources

About

Electron impact ionization of C₆₀and C₇₀: production and properties of parent and fragment ions studied with a two-sector field mass spectrometer