Formation and fragmentation of C+
                  n
                 clusters produced from a C60/C70 mixture in an electron-impact ion source

Yu, Dj.; Andersen, L. H.; Brink, Carsten; Hvelplund, P.

doi:10.1007/bf01437165

Cited by 10 publications

(2 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The important features and correlations in the fragmentation yields measured in these experiments could be well reproduced (Vandenbosch 1999) assuming an exponential distribution of excitation energies in agreement with the results of MD simulations for H 2 (Seifert and Schulte 1994) and He (Ehlich et al 1997) collisions at similar centre-of-mass collision energies. A different model was put forward to explain the fragmentation pattern observed in collisions between positive fullerene ions and H 2 at 20-200 keV collision energy (lab frame) (Hvelplund et al 1992, Yu et al 1994b. The authors assumed that multiple collisions between the target and carbon atoms in the cage could occur inducing a large rift in the cage.…”

Section: Atom/molecule/ion Impactmentioning

confidence: 99%

Fullerene reactions

2000

View full text Add to dashboard Cite

The wide range of fullerene reaction dynamics studied under well defined single-collision conditions is reviewed. It is shown that fullerenes have proven to be very fruitful model systems and have enabled considerable insight into the dynamical behaviour of complex systems with many degrees of freedom. The processes covered in this review focus on collisions at hyperthermal energies and include collision-induced fragmentation and ionization, charge transfer and endohedral fullerene formation. In addition, scattering, fusion and (multi-) fragmentation in fullerene-fullerene collisions is discussed.

show abstract

Section: Atom/molecule/ion Impactmentioning

confidence: 99%

Fullerene reactions

2000

View full text Add to dashboard Cite

show abstract

“…However, the collision cross-section for C 58 +• • measured for 20 and 30 keV ions in collisions with H 2 and Ar is at most twice that for C 60 +• • . 18 Based on these considerations, a contribution to the fragment ion pattern from the estimated 0.7% of C 70 +• • ions of higher internal energy (generated by dissociative ionization from higher fullerenes) cannot be excluded. However, especially in the light of the collision cross-section mentioned above, 18 it seems unlikely that this "impurity" of "hot" C 70 +• • ions can entirely account for the observed differences.…”

Section: Methodsmentioning

confidence: 99%

The dissociation pattern of 3 keV- C70+• colliding with He. Inaccuracies in the fragment ion intensities from linked scans

Drewello¹,

Asmus²,

Herzschuh

1995

Eur. J. Mass Spectrom.

View full text Add to dashboard Cite

show abstract

Collision‐induced dissociation of C: Effect of energy‐coupling processes on the dissociation dynamics

Mathur

Brink

Hvelplund

et al. 1995

Rapid Comm Mass Spectrometry

Self Cite

View full text Add to dashboard Cite

Dissociation of C, ions induced in 30 keV collisions with atomic and molecular gases has been studied. The pattern of negative-ion formation from C, precursors is found to be distinctly different from that obtained for positive-ion fragments from C& precursors in that the collision-induced dissociation spectrum in the former case is dominated by small negative clusters, presumably of linear geometry. Simple arguments utilizing the relationship of electrostatic properties of different molecular structures to their electron affinities and ionization energies have been invoked to rationalize these observations. The difference in the dissociation dynamics of C, and C& ions is discussed in terms of competition between different energy-coupling schemes involving either electronic degrees of freedom or nuclear (vibrational) degrees of freedom.There remains a paucity of experimental information on the energetics and dynamics of dissociation processes involving negatively-charged fullerene ions. We report here the results of measurements of the dissociation spectra obtained when C, ions undergo collisions, at an energy of 30keV, with atomic and molecular gases. The pattern of negatively-charged fragment ion formation from C, precursors is found to be distinctly different from the corresponding pattern obtained for positive-ion fragments from C& precursors. Whereas the latter experiments indicate that the fragmentation pattern is dominated by loss of C2 units, giving rise to a range of positively-charged, even-numbered fullerene ion peaks from C& to C&, as well as lower-mass, evenand odd-numbered fragments from C' to C&, our experiments with C, ions offer evidence that no negatively-charged fullerene ions are formed in the range C, to C; ; our fragmentation spectrum is dominated by low-mass negatively-charged ions in the range from C-to C;. Our results appear to indicate that fragmentation of C, is likely to be accompanied by simultaneous electron ejection. We discuss this difference in the dissociation patterns of negatively-and positively-charged C, in terms of the recentlydeveloped understanding of delayed ionization processes in large polyatomic molecules. Our results manifest the competition between two different energycoupling processes, involving electronic degrees of freedom on the one hand and nuclear (vibrational) degrees of freedom on the other.Ionization of small, isolated (gas-phase) molecules is well-known to be a 'prompt' process in the sense that in any photoionization or collisional ionization situation, once the molecular ionization energy is exceeded, the electron is ejected from the molecular charge cloud on a femtosecond timescale. Even for indirect ionization processes, such as initial collisional excitation to a doubly-excited electronic state lying in the ionization continuum and subsequent autoionization, the 'prompt' character of the overall electron ejection process continues to be maintained. However, ionization ' Author for correspondence. of very large molecular species need not always be 'pro...

show abstract

Formation and fragmentation of C+ n clusters produced from a C60/C70 mixture in an electron-impact ion source

Cited by 10 publications

References 18 publications

Fullerene reactions

Fullerene reactions

The dissociation pattern of 3 keV- C70+• colliding with He. Inaccuracies in the fragment ion intensities from linked scans

Collision‐induced dissociation of C: Effect of energy‐coupling processes on the dissociation dynamics

Contact Info

Product

Resources

About