Fission of doubly ionized calcium clusters
نویسندگان
چکیده
Cluster ions, CaN and Ca 2þ N , containing up to N = 8 atoms are studied within density functional theory. Ground and first excited states, and ionization energies are reported for all sizes. At zero temperature Ca2þ 3 and Ca 2þ 4 are linear, whereas Ca 2þ 5 through Ca 2þ 7 undergo structural transitions from 3D-configurations into linear ions below 600 K. As a consequence, fission that occurs above 600 K starts from linear configurations. Ca2þ 8 has an hexagonal bipyramidal structure. The preferred fission channels are Ca2þ N ! Ca þ þ CaN 1 with fission barriers smaller than the evaporation energy up to Ca 2þ 7 . However, Ca 2þ 8 presents a large fission barrier and would rather evaporate one atom than undergo fission. 2004 Elsevier B.V. All rights reserved.
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