Nuclear linear-chain structure arises in carbon-14

Abstract The shape and internal structure of an atomic nucleus can change significantly with increasing excitation energy, angular momentum, or isospin asymmetry. As example this structural evolution, linear-chain configurations in carbon heavier isotopes have been predicted for decades. Recent studies found non-stability 12 C while evidenced its appearance 16 C. It is then necessary to investigate the molecular structures 14 clarify exact location on nuclear chart where begins emerge, thus benchmark theoretical models. Here we show a cluster-decay experiment all final particles coincidentally detected, allowing high Q -value resolution, clear decay-path selection. Unambiguous spin-parity analyses are conducted, strongly evidencing emergence π -bond rotational band present results encourage further even longer chain neutron-rich nuclei.