Collision-induced electron detachment of carbon clusters

Moriwaki, Toshimichi; Shiromaru, H.; Achiba, Yohji

doi:10.1007/s004600050024

Cited by 14 publications

(11 citation statements)

References 25 publications

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“…We mention some of them: ͑1͒ several laser-induced ultrafast phase transitions have been observed [1][2][3] where interesting transitions between two crystalline structures could occur, ͑2͒ the excitation of the electrons in aggregate interacting with rapid charged monoatomic ion where ionization and capture could occur; 4 and ͑3͒ femtosecond neutralization dynamics in cluster-solid surface collisions. 5 In the case of the ion-cluster collision, two main procedures have been used: either a semiclassical limit of a time dependent Hartree-Fock description 6 or a time dependent density functional approach 7 to tackle problems involving large cluster, but in principle such procedures do not treat quite well the nonadiabatic response. Theoretical analysis have been carried out: for the case of the analysis of the laser induced femtosecond graphitization of diamond 8 or in the electron emission yield of charged clusters colliding with different surfaces at low energies.…”

Section: Introductionmentioning

confidence: 99%

Nonadiabatic response of a finite fermion system to a time perturbation

2001

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The nonadiabatic response to a time perturbation applied to a finite system modeled with the Hubbard Hamiltonian has been investigated in the case where one atom of the cluster is continuously uncoupled ͑monofragmentation . . . ͒. An exact solution has been derived using numerical procedures for the octahedron cluster in the ͑4↑, 4↓͒ electronic configuration. A comparison of the time evolution of the population n(t) on the moving atom has been carried out between our exact result and the so-called ''one-determinant method,'' which is based on the propagation of only one Slater determinant. An analysis of the discrepancy between the two results is illustrated on the dimer case AB (A B) in the ͑1↑, 1↓͒ configuration. The calculations show that more excitations are occurring in the exact calculation leading first to a more efficient initial filling of the uncoupled atom population and secondly to a smaller value of n(t) at the end of the process (n f ). The electronic correlation modifies the dynamics of the process but slightly n f .

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Section: Introductionmentioning

confidence: 99%

Nonadiabatic response of a finite fermion system to a time perturbation

2001

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“…It is normally accepted wisdom [3] that clusters C n with n ≤ 10 take the form of linear chains, while for 11 ≤ n < 32 cyclic structures dominate (see however [4]). For n ≥ 32 the cage structure (fullerenes) may dominate depending on the production method, especially so for the negative clusters [5,6]. The interplay between electron affinities and cluster geometry is most likely an important factor for a better understanding of collisional electron detachment in energetic collisions between negative clusters and static gas targets.…”

Section: Introductionmentioning

confidence: 99%

Electron detachment and fragmentation in collisions between 50 keV C − n (1 ≤ n ≤ 86) clusters and H2

Shen

Brink

Hvelplund

et al. 1997

Z Phys D - Atoms, Molecules and Clusters

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The destruction cross section for 50 keV negative carbon clusters C − n (1 ≤ n ≤ 88) in collisions with H 2 is reported. The dominant destruction channel is believed to be electron detachment. The measured cross section values are compared with theoretical values based on a simple geometrical model of the carbon cluster, and structural information is obtained. Fragment spectra of both positive and negative clusters are also recorded and fragmentation patterns are discussed in relation to fragmentation energies and ionization potentials.

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“…A variety of collision experiments between clusters and solid surfaces were performed during the last decades. These can be grouped into investigations involving (i) surface modification by cluster bombardment or deposition [1,2], (ii) scattering of intact species and their fragments [3,4], and (iii) electron emission [5][6][7]. Such studies gave, for instance, insight into the stability of small particles and, to a certain extent, their geometry; energetic cluster impact can modify the formation of thin films.…”

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confidence: 99%

Femtosecond Neutralization Dynamics in Cluster-Solid Surface Collisions

et al. 1997

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Experimental results for the relative electron emission yields g͑N͒ of charged clusters colliding at low energies with different surfaces are presented. For fixed collision energy a remarkable cluster size dependence of g͑N͒ is obtained using highly oriented pyrolytic graphite as target. By studying theoretically the collision process within a microscopic model we find that the nonadiabatic survival probability of the charged clusters shows the same behavior as g͑N͒. Thus, g͑N͒ reflects the femtosecond neutralization dynamics during the collision, which may result in damped Stückelberg oscillations for targets with narrow densities of states. [S0031-9007(97)04139-2] PACS numbers: 79.20. Rf, 34.50.Dy, 36.40.Wa Quantum effects observed when two macroscopic objects interact via a tunneling gap are always exciting as they might be important for future nanoelectronic devices. In addition they sometimes allow intriguing insight into the physics of quantum states induced by the charge confinement in a system of reduced dimensionality. As a matter of fact, however, the dynamics of the electron motion usually remains hidden due to the extremely short time scales involved. Only recently the pumpprobe techniques with femtosecond laser light pulses have started to give some progress in the understanding of such processes.Here we will raise the question of whether the transient character of a collision process of a charged metal atom cluster with a solid surface might elucidate the dynamics of the electron motion between the two partners. Will there be a single electron jump as in a classical picture, or might there be a resonant tunneling process where the charge density-once the collision partners overcome a minimum threshold distance-fluctuates between cluster and surface?So far, this question has not been tackled. A variety of collision experiments between clusters and solid surfaces were performed during the last decades. These can be grouped into investigations involving (i) surface modification by cluster bombardment or deposition [1,2], (ii) scattering of intact species and their fragments [3,4], and (iii) electron emission [5][6][7]. Such studies gave, for instance, insight into the stability of small particles and, to a certain extent, their geometry; energetic cluster impact can modify the formation of thin films. During energetic impact there exist nonequilibrium conditions similar to those in shock tubes, but on a very different time scale, a femtosecond scale. New types of chemical reactions, characterized by extremely high density, pressure, and kinetic temperature, are expected to occur. All these experiments give no hints of possible quantum effects, which are the topic of this Letter.The setup of the experiment for collision induced electron emission measurements will be described in detail elsewhere [8]. In short, the clusters are produced in a source of the PACIS type [9]. After acceleration to their final collision energy E coll , they are mass separated in a Wien velocity filter (Colutron 600 B) which...

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Collision-induced electron detachment of carbon clusters

Cited by 14 publications

References 25 publications

Nonadiabatic response of a finite fermion system to a time perturbation

Nonadiabatic response of a finite fermion system to a time perturbation

Electron detachment and fragmentation in collisions between 50 keV C − n (1 ≤ n ≤ 86) clusters and H2

Femtosecond Neutralization Dynamics in Cluster-Solid Surface Collisions

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