Shape transition and shape coexistence in atomic clusters and nuclei

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We investigate the signature of shape transition and shape coexistence in small atomic clusters and other mesoscopic systems, such as atomic nuclei. One of the best known examples is the prolate-compact shape transition/coexistence phenomenon observed in mobility experiments on Si clusters.[1] Using a hierarchical strategy that features an extensive tight-binding-based search of the energy surface, followed by a full density functional theory investigation of the most stable structures, we recently determined the lowest-energy clusters across the range n=2 to 28.[2] The calculated properties of these clusters are in very good agreement with available measurements of dissociation energies, ionization energies and ion mobilities, providing strong evidence that these structures are the ones found in experiments. The calculations clearly exhibit a transition in the relative stability of prolate and compact clusters between n=25 and 26, coinciding exactly with the experimental behavior. The lowest energy prolate and compact structures are found almost degenerate, justifying the coexistence of shapes observed in the experiment. The binding energy per atom of the ground states vs N-1/3 exhibits a long plateau in the transition/coexistence region, suggesting that this phenomenon may be related to a relatively small surface tension. Similar behavior was recently found in the isotope 152 of the nucleus of the element Sm, for which the ground sate, J π = 0+, is known to be very deformed, and the first excited Jπ = 0+, is compact. A similar signature in the binding energy per atom of the Sm isotopes can be also extracted from the available experimental data.

Original languageEnglish
Title of host publicationNUCLEI AND MESOSCOPIC PHYSICS
Subtitle of host publicationWorkshop on Nuclei and Mesoscopic Physics, WNMP 2004
Number of pages6
StatePublished - Jul 8 2005
EventNUCLEI AND MESOSCOPIC PHYSICS: Workshop on Nuclei and Mesoscopic Physics, WNMP 2004 - East Lansing, MI, United States
Duration: Oct 23 2004Oct 26 2004

Publication series

NameAIP Conference Proceedings
ISSN (Print)0094-243X
ISSN (Electronic)1551-7616


ConferenceNUCLEI AND MESOSCOPIC PHYSICS: Workshop on Nuclei and Mesoscopic Physics, WNMP 2004
Country/TerritoryUnited States
CityEast Lansing, MI


  • Atomic clusters
  • Samarium
  • Shape coexistence
  • Shape transition
  • Silicon


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