Abstract
New experimental data on the inelastic scattering of α-particles on 13C at $$E(\alpha ) = 65$$ and 90 MeV with the excitation of the $$1{\text{/}}2_{3}^{ - }$$ state are reported. Data are analyzed using the modified diffraction model. The determined rms radius of this state coincides within errors with the radius of the $$1{\text{/}}2_{2}^{ - }$$ 8.86 MeV state in 13C and the Hoyle state in 12C. This result is an argument for a similar structure of these states. The unusual result for the compact 3/2– 9.90 MeV state in 13C has been tested by considering its isobar-analog 3/2– 9.48 MeV state in 13N. It has been found that these states have a normal non-increased radius.