3alpha clustering in the excited states of 16C

TL;DR

This paper investigates alpha cluster states in 16C, revealing two types—triangular and linear-chain—with distinct configurations and energies, and discusses their structure, correlations, and rotational properties using molecular orbital models.

Contribution

It provides the first detailed analysis of alpha clustering in 16C's excited states, identifying two distinct cluster configurations and their structural characteristics.

Findings

Triangular and linear-chain alpha cluster states exist in 16C.

Linear-chain state has a very large moment-of-inertia and becomes yrast at J=10.

The structure of linear-chain states aligns with molecular orbital predictions.

Abstract

The alpha cluster states of 16C are investigated by using the antisymmetrized molecular dynamics. It is shown that two different types of alpha cluster states exist: triangular and linear-chain states. The former has an approximate isosceles triangular configuration of alpha particles surrounded by four valence neutrons occupying sd-shell, while the latter has the linearly aligned alpha particles with two sd-shell neutrons and two pf-shell neutrons. It is found that the structure of the linear-chain state is qualitatively understood in terms of the 3/2 pi- and 1/2 sigma- molecular orbit as predicted by molecular-orbital model, but there exists non-negligible Be+alpha+2n correlation. The band-head energies of the triangular and linear-chain rotational bands are 8.0 and 15.5 MeV, and the latter is close to the He+Be threshold energy. It is also shown that the linear-chain state becomes the yrast sstate at J=10 with excitation energy 27.8 MeV owing to its very large moment-of-inertia comparable with hyperdeformation.