Spectacular confinement induced peculiarities in the structure of semifilled shell atoms

The structure and spectra of atoms, spatially confined by various types of confinements whose sizes are commensurable with an atomic size, have seized minds of theorists starting since early days [1,2] to now [3]. This is because a confined atom concept provides insights into various aspects of interdisciplinary significance [3]. The present article reports on novel discoveries made, specifically, for semifilled shell atoms under confinement. The latter is simulated by a repulsive penetrable spherical potential of an adjustable inner radius $r_{0}$. There, spectacular confinement induced effects termed orbital breathing, fusion, fission, and re-ordering with changing $r_{0}$ have been unraveled. The discovered effects are exemplified by calculated data for confined Li($\rm 2s^{1}$), N($\rm 2p^{3}$), P($\rm 3p^{3}$), and Cr($\rm 3d^{5}$$\rm4s^{1}$). The underlying physics for the effects is explained.\\[4pt] [1] A. Michels, J. de Boer, and A. Bijl \textit{Physica} \textbf{4} 981 (1937)\\[0pt] [2] A. Sommerfeld and H. Welker {\it Ann. Phys.} {\bf 32} 56 (1938)\\[0pt] [3] In: \textit{Adv. Quant. Chem.}, Volumes \textbf{57} and \textbf{58} (2009).