Fragmentation phase transitions in atomic clusters III

Schapiro, O.; Kuntz, P. J.; Möhring, K.; Hervieux, Paul-Antoine; Gross, D. H. E.; Madjet, Mohamed

doi:10.1007/s004600050314

Cited by 22 publications

(18 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Also, in a statistical model [14] that assumes an ergodic distribution of fission fragments for a system confined to a small volume, evidence was found for a first-order "fragmentation phase transition" from a regime with a large residual fragment at low excitation energies to a regime with only small fragments at high excitation energies. We do not observe clear evidence for such an effect in the present data, although our statistics and range of study are too limited.…”

Section: +mentioning

confidence: 99%

“…These studies and others yield important insights into the behavior of matter at the small size limit and the size-dependent evolution toward bulk properties. Much recent work on fission has been devoted to metallic clusters, both experimentally [2][3][4][5][6][7][8][9][10][11] and theoretically [4,9,[12][13][14][15][16]. Fission of metallic clusters is particularly interesting on account of the similarities and differences with the nuclear fission process [12].…”

mentioning

confidence: 99%

See 1 more Smart Citation

Charge-Induced Fragmentation of Sodium Clusters

et al. 2001

View full text Add to dashboard Cite

The fission of highly charged sodium clusters with fissilities X > 1 is studied by ab initio molecular dynamics. Na244+ is found to undergo predominantly sequential Na3 + emission on a time scale of 1 ps, while Na24 Q+ (5 ≤ Q ≤ 8) undergoes multifragmentation on a time scale ≥ 0.1 ps, with Na + increasingly the dominant fragment as Q increases. All singly-charged fragments Nan + up to size n = 6 are observed. The observed fragment spectrum is, within statistical error, independent of the temperature T of the parent cluster for T ≤ 1500 K. These findings are consistent with and explain recent trends observed experimentally. 36.40.Qv, 36.40.Wa, 31.15.Qg, 31.15.Ew Starting with the work of Sattler et al.[1] on van der Waal's clusters, the study of the fragmentation (fission) of charged atomic or molecular clusters has proved a valuable experimental tool for investigating the intrinsic stability and binding forces of these objects. These studies and others yield important insights into the behavior of matter at the small size limit and the size-dependent evolution toward bulk properties. Much recent work on fission has been devoted to metallic clusters, both experimentally [2][3][4][5][6][7][8][9][10][11] and theoretically [4,9,[12][13][14][15][16]. Fission of metallic clusters is particularly interesting on account of the similarities and differences with the nuclear fission process [12]. Over a century ago, Lord Rayleigh [17] studied the problem of the time development of the Coulomb instability of a surface-charged liquid drop, and conjectured that the excess charge would be removed by the emission of jets, rather than by fission into two parts of more or less equal size (as occurs for nuclei, where the charge is distributed uniformly through the volume).According to the Rayleigh criterion [17], a charged liquid drop is unstable against Coulomb forces when its fissility X > 1, where X = E Coul /(2E surf ) is proportional to the ratio of the Coulomb to surface energy of the drop. For a metallic cluster M N Q+ , assumed spherical with radius r s N 1/3 (r s is the Wigner-Seitz radius for the metal), this gives X = (16πr 3 s σ) −1 Q 2 /N , where σ is the surface tension, or X ≈ 2.5Q 2 /N for Na N Q+ . Now, fission experiments on metallic clusters where the cluster is charged by laser ionization [2][3][4][5][6][7] have so far produced only clusters with X < 1, for which an energy barrier exists against fission. Thermally activated fission may be observed, however, and the dominant charged fragment is found to be Na 3 + , which has a closed electronic shell and is particularly stable; Na + has not so far been observed. In a different type of experiment [8][9][10][11], sodium clusters are ionized by collision with a beam of highly charged ions, a technique that is expected to allow study of a much wider range of X and cluster temperatures. Coincidence measurements reveal multifragmentation processes in some cases, often with Na + as the dominant fragment. In this Letter, we offer the first systematic dynamical study ...

show abstract

Section: +mentioning

confidence: 99%

mentioning

confidence: 99%

Charge-Induced Fragmentation of Sodium Clusters

et al. 2001

View full text Add to dashboard Cite

show abstract

“…In our fragmentation model, since the properties of diatomic or the triatomic molecules are well known, we used for dimers and trimers the values of the vibrational frequencies and the calculated principal moments of inertia given in Tab.I. We have improved our model by taking polarization effects into account [17]. As discussed in details in ref.…”

Section: Alkali Metal Clustersmentioning

confidence: 99%

“…As discussed in details in ref. [17], we do not allow the fragments to be closer than a certain distance which is fixed at 1.0Å for all the elements studied.…”

Section: Alkali Metal Clustersmentioning

confidence: 99%

“…In using the Microcanonical Metropolis Monte Carlo method (MMMC), described in details in [15,14], see also the first paper of this series [16], we present the fragmentation of doubly charged clusters of the elements Li, K, Na and Sb. In the next paper of this series [17] we will study the implication of the accessible phase space on the fragmentation of multiply (Z ≥ 2) charged alkali clusters. A fourth paper [18] will discuss the relation of the fragmentation phasetransition to the liquid-gas transition of the bulk.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Fragmentation phase transition in atomic clusters II

Madjet

Hervieux

Gross

et al. 1997

Z Phys D - Atoms, Molecules and Clusters

Self Cite

View full text Add to dashboard Cite

We present a statistical fragmentation study of doubly charged alkali (Li, Na, K) and antimony clusters. The evaporation of one charged trimer is the most dominant decay channel (asymmetric fission) at low excitation energies. For small sodium clusters this was quite early found in molecular dynamical calculations by Landman et al. [1]. For doubly charged lithium clusters, we predict Li + 9 to be the preferential dissociation channel. As already seen experimentally a more symmetric fission is found for doubly charged antimony clusters. This different behavior compared to the alkali metal clusters is in our model essentially due to a larger fissility of antimony. This is checked by repeating the calculations for Na ++ 52 with a bulk fissility parameter set artificially equal to the value of Sb.

show abstract

Fragmentation phase transition in atomic clusters IV

Gross

Madjet

1997

Z. Phys. B

View full text Add to dashboard Cite

Fragmentation phase transitions in atomic clusters III

Cited by 22 publications

References 21 publications

Charge-Induced Fragmentation of Sodium Clusters

Charge-Induced Fragmentation of Sodium Clusters

Fragmentation phase transition in atomic clusters II

Fragmentation phase transition in atomic clusters IV

Contact Info

Product

Resources

About