An investigation of the $N=20{}^{36}\mathrm{S}$ nucleus has been performed through a detailed study of the ${}^{36}\mathrm{S}(p,d){}^{35}\mathrm{S}$ neutron-removal reaction, employing a 66-MeV proton beam at iThemba Laboratory for Accelerator Based Sciences and an innovative target design. Using the high-resolution $K$ = 600 magnetic spectrometer, 98 states in ${}^{35}\mathrm{S}$ were identified up to 16-MeV excitation energy, including 47 previously unobserved states. Angular distributions and spectroscopic factors, including isobaric analog-state contributions, were extracted for 81 levels. A pronounced $j$ dependence in the angular distributions of $\ell =2$ states provides refined insights into the spin-orbit splitting. Finite-range adiabatic distorted-wave approximation calculations qualitatively reproduce the observed $j$ dependence. Comparisons of the measured $1d_{5/2}$ spectroscopic strength distribution with large-scale shell-model and ab initio calculations show good agreement overall, and the robustness of the $N=20$ shell closure in ${}^{36}\mathrm{S}$ is confirmed when comparing the relatively low $fp$ orbital occupancies in ${}^{40}\mathrm{Ca}$ and ${}^{36}\mathrm{S}$ across the Fermi surface. This study underscores the utility of neutron-removal reactions in probing nuclear structure and the Fermi surface of $sd$ nuclei and beyond. The findings advance our understanding of shell evolution and offer constraining data for theoretical models.

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• Energy levels
• H & He induced nuclear reactions
• Nuclear spin & parity
• Nuclear structure & decays
• Transfer reactions
• 20 ≤ A ≤ 38