Many-electron atom confinement by a penetrable prolate spheroidal cavity S. A. Cruz, C. Díaz-García, D. Garrido-Aguirre and R. Reyes-García Eur. Phys. J. D, 75 4 (2021) 143 Published online: 29 April 2021 DOI: 10.1140/epjd/s10053-021-00150-3