  In this work we study alpha-clustering in 18Ne and compare it with what is
known about clustering in the mirror nucleus 18O. The excitation function of
18Ne was measured in inverse kinematics from the resonant elastic scattering
reaction of 14O on 4He in the excitation energy range from 8 to 17 MeV, using
the active target TexAT. The analysis was performed using a multi-channel
R-matrix approach. Detailed spectroscopic information is obtained from the
R-matrix analysis: excitation energy of the states, spin and parity as well as
partial alpha and total widths. This information is compared with theoretical
models and previous data. Clustering structures appear to be robust and mostly
isospin symmetric. A good correspondence was found between the levels in 18O
and 18Ne. We carried out an extensive shell model analysis of the experimental
data. This comparison suggests that strongly clustered states remain organized
in relation to the corresponding reaction channel identified by the number of
nodes in the relative alpha plus core wave function. The agreement between
theory and experiment is very good and especially useful when it comes to
understanding the clustering strength distribution. The comparison of the
experimental data with theory shows that certain states, especially at high
excitation energies, are significantly more clustered than predicted. This
indicates that the structure of these states is collective and is aligned
towards the corresponding alpha reaction channel.
