In ion-fullerene C60 frontal collisions, an amount of energy is deposited in the C60 target leading to the fragmentation of the C60. Theoretical and experimental investigations have demonstrated that the fragmentation...In ion-fullerene C60 frontal collisions, an amount of energy is deposited in the C60 target leading to the fragmentation of the C60. Theoretical and experimental investigations have demonstrated that the fragmentation scheme of the C60 depends not only on the total excitation energy but also on the nature of the primary electronic and nuclear excitation mechanism. Up to now, the commonly accepted interpretation of the observed mass spectra obtained in ion-C60 experiments is to consider the multi-fragmentation of the C60 being mainly due to the primary electronic interaction. The efficient transfer of the electronic excitation energy towards vibronic modes induces the breakup of the C60 cage in a statistical decay process.展开更多
Citation of the C60^4+ is the same in the two collisions. The strong C+ peak produced in Ar^+-C60 must be due to the elastic collisions (nuclear stopping), because the Ar+ is heavy enough to knock out the C^+ from C60...Citation of the C60^4+ is the same in the two collisions. The strong C+ peak produced in Ar^+-C60 must be due to the elastic collisions (nuclear stopping), because the Ar+ is heavy enough to knock out the C^+ from C60 molecule. In general, the excitation energy depends on the projectile velocity, charge, and mass. Direct vibronic excitation by elastic collisions (nuclear stopping) is predicted for slow heavy ions, while the electronic excitation (electronic stopping) is dominant for fast ions[1]. For example, Schlatholter, et al.[2] found a strong velocity effect in collisions of He^+ with fullerene in the velocity range from 0.1 to 1 a.u. With increasing velocity, the C2 evaporation process decreases and the multi-fragmentation is linearly increasing.展开更多
With the conic electrode trap,the lifetime of C^(r+)_(60)was measured in 56 keV Ar^(8+)-C60 collisions.The outgoing projectiles Ar^((8-s)+),on which s captured electrons are stabilized,are selected by an electrostatic...With the conic electrode trap,the lifetime of C^(r+)_(60)was measured in 56 keV Ar^(8+)-C60 collisions.The outgoing projectiles Ar^((8-s)+),on which s captured electrons are stabilized,are selected by an electrostatic analyzer.The ejected electrons and the recoil ions were extracted from the interaction region by a high transverse electric field E=1 kV/cm.After extraction the electrons were accelerated towards a semiconductor detector(PIPS)biased at 20 kV,which gives the information on the number of emitted electrons in the react.展开更多
In highly charged ions-C_(60)collisions,the fragmentation processes have been studied up to C^(9+)_(60).For low charge state of C^(q+)_(60)(g=1-4)the C_(2) evaporation processes have been observed.The fission processe...In highly charged ions-C_(60)collisions,the fragmentation processes have been studied up to C^(9+)_(60).For low charge state of C^(q+)_(60)(g=1-4)the C_(2) evaporation processes have been observed.The fission processes consisting of the emission of light charged fragments have been observed typically for charge state ranging from q=3 to q=9.The multi-fragmentation processes appear from 5=4 and became quickly dominant for higher charge states.展开更多
文摘In ion-fullerene C60 frontal collisions, an amount of energy is deposited in the C60 target leading to the fragmentation of the C60. Theoretical and experimental investigations have demonstrated that the fragmentation scheme of the C60 depends not only on the total excitation energy but also on the nature of the primary electronic and nuclear excitation mechanism. Up to now, the commonly accepted interpretation of the observed mass spectra obtained in ion-C60 experiments is to consider the multi-fragmentation of the C60 being mainly due to the primary electronic interaction. The efficient transfer of the electronic excitation energy towards vibronic modes induces the breakup of the C60 cage in a statistical decay process.
文摘Citation of the C60^4+ is the same in the two collisions. The strong C+ peak produced in Ar^+-C60 must be due to the elastic collisions (nuclear stopping), because the Ar+ is heavy enough to knock out the C^+ from C60 molecule. In general, the excitation energy depends on the projectile velocity, charge, and mass. Direct vibronic excitation by elastic collisions (nuclear stopping) is predicted for slow heavy ions, while the electronic excitation (electronic stopping) is dominant for fast ions[1]. For example, Schlatholter, et al.[2] found a strong velocity effect in collisions of He^+ with fullerene in the velocity range from 0.1 to 1 a.u. With increasing velocity, the C2 evaporation process decreases and the multi-fragmentation is linearly increasing.
文摘With the conic electrode trap,the lifetime of C^(r+)_(60)was measured in 56 keV Ar^(8+)-C60 collisions.The outgoing projectiles Ar^((8-s)+),on which s captured electrons are stabilized,are selected by an electrostatic analyzer.The ejected electrons and the recoil ions were extracted from the interaction region by a high transverse electric field E=1 kV/cm.After extraction the electrons were accelerated towards a semiconductor detector(PIPS)biased at 20 kV,which gives the information on the number of emitted electrons in the react.
文摘In highly charged ions-C_(60)collisions,the fragmentation processes have been studied up to C^(9+)_(60).For low charge state of C^(q+)_(60)(g=1-4)the C_(2) evaporation processes have been observed.The fission processes consisting of the emission of light charged fragments have been observed typically for charge state ranging from q=3 to q=9.The multi-fragmentation processes appear from 5=4 and became quickly dominant for higher charge states.
