Resonant inter-Coulombic decay processes from atom to fullerene and backward in the photoionization of Ar@C$_{60}$

In a theoretical study of the photoionization of Ar@C$_{60}$ we find the evidence of strong decay probability of Ar single-core-electron excited states through degenerate ionization continua of the encapsulating fullerene \textit{via} a mechanism known as the resonant inter-Coulombic decay (RICD) [1]. The resulting resonance structures in C$_{60}$ subshell cross sections are found to assume significantly different shapes from those of the pure autoionizing resonances of Ar. We further predict an abundance of ``backward RICD'' processes. These are the decay of C$_{60}$ inner-shell excitations through Ar continua. Several of such resonances are also obtained in 3$p$ and 3$s$ cross sections of the confined Ar. Mutual hybridizations between some of Ar and C$_{60}$ orbitals influence the properties of these resonances. Calculations are carried out on a framework of time-dependent local density approximation where the fullerene ion-core of sixty C$^{4+}$ ions is smudged into a continuous jellium distribution [2].\\[4pt] [1] V. Averbukh and L.S. Cederbaum, \textit{Phys. Rev. Lett.} \textbf{96}, 053401 (2006);\\[0pt] [2] M.E. Madjet, T. Renger, D.E. Hopper, M.A. McCune, H.S. Chakraborty, J.-M. Rost, and S.T. Manson, \textit{Phys. Rev. }A \textbf{81}, 013202 (2010).