EGAS41 - Swansea University

41 st EGAS CP 69 Gdańsk 2009
Fragmentation of multiply charged clusters
M. Nakamura ∗
College of Science and Technology, Nihon University, Japan
∗ Corresponding author: mooming@phys.ge.cst.nihon-u.ac.jp
A multiply charged cluster is stable if its size is larger than the appearance size. Otherwise,
the cluster fragments automatically. The stability and fragmentation of van der Waals
clusters have been discussed within the framework of the liquid drop model (LDM) [1].
Recently, the author has studied the role of geometrical shell effect to the appearance size
of multiply charged clusters [2,3]. Here we discuss influences of the shell effect on the decay
of multiply charged clusters. The shell energy is estimated from the calculation of the
energy of Lennard-Jones clusters [4,5]. Fig. 5 shows the energy barriers for fragmentation,
Kr + 53 → Kr+ k +Kr+ 53−k as a function of k. By taking account of the shell effect, the predicted
decay pattern changes completely. Although the LDM predicts that fragmentation is
possible for all k for 10 < k < 43, only k = 13 (a magic number) is the energetically
accessible decay channel if we consider the shell effect. This fact indicates us the shell
effect plays a significant role in the decay of multiply charged clusters.
0.008
0.006
0.004
0.002
10 20 30 40 50
Figure 1: Kr + 53 → Kr+ k + Kr+ 53−k
. Solid line: calculation including shell effect; Dashed line:
calculation with LDM
Acknowledgment
This work has been financially supported by Matsuo Foundation and by Nihon University Individual
Research Grant in 2009.
References
[1] O. Echt et al., Phys. Rev. A 38, 3236 (1988)
[2] M. Nakamura, Chem. Phys. Lett. 449, 1 (2007)
[3] M. Nakamura, P.-A. Hervieux, Chem. Phys. Lett. 428, 138 (2006)
[4] D. Wales, J. Doye, J. Phys. Chem. A 101, 5111 (1997)
[5] Y. Xiang et al., J. Phys. Chem. A 108, 3586 (2004)
129