(Received January 17, 2002)
The structure of C isotopes are investigated using a microscopic α+α+α+n+n… model based on the molecular orbit (MO) model. The stability of the linear-chain of 3α with respect to the breathing mode and the bending mode for various neutron configurations is investigated. The combination of the valence neutrons in the π- and the σ-orbit is promising to stabilize for these modes, and the excited state of 16C with the (3/2-π)2(1/2-σ)2 configuration for the four valence neutrons is one of the most promising candidates for such structure. Furthermore, the equilateral-triangular shape of 3α surrounded by valence neutrons is suggested for 14C based on a microscopic cluster model. The 3-, 4- and 5- members of this rotational band appear around the 10Be+α threshold, and these calculated states correspond to the experimentally observed 3- state (9.80 MeV) and 4- state (11.67 MeV). A positive-parity rotational band (0+, 2+, 4+) also arises around this threshold energy, and these results suggest that the picture of inversion doublet structure works also in neutron-rich nuclei.
URL : http://ptp.ipap.jp/link?PTPS/146/207/
DOI : 10.1143/PTPS.146.207