5s correlation confinement resonances in Xe-endo-fullerenes

Spectacular trends in the modification of the Xe 5s photoionization via interchannel coupling with confinement resonances emerging in the Xe 4d giant resonance upon photoionization of the Xe@C60, Xe@C240 and Xe@C60@C240 endo-fullerenes are theoretically unraveled and interpreted.Comment: 1 page, 1 figure. 2011 International Conference on Photonic, Electronic, and Atomic Collisions (Belfast, UK, 2011). Paper number We15

Confinement induced orbital breathing, fusion, fission and re-ordering in semifilled shell atoms

Alternate contraction and drastic expansion, i.e., `breathing' of electronic subshells, the effects of fusion of two subshells into one subshell and its subsequent fission (splitting) into the original subshells, as well as multiple alteration of the order of subshells in confined semifilled shell atoms with a progressively narrowing confinement are theoretically discovered. The confinement is represented by a repulsive penetrable spherical potential of an inner radius $r_{0}$. The effects are exemplified by calculated data for confined semifilled shell atoms from the second, third and fourth rows of Mendeleev's table - Li, N, P and Cr atoms with semifilled ${2\rm s}^{1}$, ${2\rm p}^{3}$, ${3\rm p}^{3}$ and ${3\rm d}^{5}$ subshells, respectively - for the completeness of the study. The underlying physics behind the discovered effects is explained.Comment: 15 pages, 7 figures; to be submitted to J. Phys. B: At. Mol. Opt. Phy

Confinement and electron correlation effects in photoionization of atoms in endohedral anions: Ne@C60^{z-}

Trends in resonances, termed confinement resonances, in photoionization of atoms A in endohedral fullerene anions A@C60^{z-} are theoretically studied and exemplified by the photoionization of Ne in Ne@C{60}^{z-}. Remarkably, above a particular nl ionization threshold of Ne in neutral Ne@C60 (I_{nl}^{z=0}), confinement resonances in corresponding partial photoionization cross sections sigma_{nl} of Ne in any charged Ne@C60^{z-} remain almost intact by a charge z on the carbon cage, as a general phenomenon. At lower photon energies, omega < I_{nl}^{z=0}, the corresponding photoionization cross sections develop additional, strong, z-dependent resonances, termed Coulomb confinement resonances, as a general occurrence. Furthermore, near the innermost 1s ionization threshold, the 2p photoionization cross section sigma_{2p} of the outermost 2p subshell of thus confined Ne is found to inherit the confinement resonance structure of the 1s photoionization spectrum, via interchannel coupling. As a result, new confinement resonances emerge in the 2p photoionization cross section of the confined Ne atom at photoelectron energies which exceed the 2p threshold by about a thousand eV, i.e., far above where conventional wisdom said they would exist. Thus, the general possibility for confinement resonances to resurrect in photoionization spectra of encapsulated atoms far above thresholds is revealed, as an interesting novel general phenomenon.Comment: 6 pages, 4 figures, Latex2e, jpconf.cls styl

Revivification of confinement resonances in the photoionization of AA@C60_{60} endohedral atoms far above thresholds

It is discovered theoretically that significant confinement resonances in an $nl$ photoionization of a \textit{multielectron} atom $A$ encaged in carbon fullerenes, A@C$_{60}$, may re-appear and be strong at photon energies far exceeding the $nl$ ionization threshold, as a general phenomenon. The reasons for this phenomenon are unraveled. The Ne $2p$ photoionization of the endohedral anion Ne@C$_{60}^{5-}$ in the photon energy region of about a thousand eV above the $2p$ threshold is chosen as case study.Comment: 3 pages, 1 figure, Revtex

Xe 4d photoionization in Xe@C60, Xe@C240, and Xe@C60@C240

Re-evaluated parameters for the square-well potential model for photoionization of endo-fullerenes are proposed and employed to reveal the spectacular modifications in the Xe 4d photoionization giant resonance along the path from Xe@C60 to Xe@C240 to multi-walled Xe@[email protected]: 1 page, 1 figure. 2011 International Conference on Photonic, Electronic, and Atomic Collisions (Belfast, UK, 2011), abstract Tue13

Angle-differential elastic electron scattering off C60_{60}: A simple semi-empirical theory versus experiment

We prove in the present paper that a simple modeling of a complicated highly polarizable C$_{60}$ target by a rectangular (in a radial coordinate) square well potential in combination with the static polarization potential provides a viable approximation for a low-energy elastic electron scattering off this target. The proof is based on the results of the comparison of the calculated angle-differential elastic electron scattering cross section off C$_{60}$ versus corresponding experimental data.Comment: 4 pages, 3 figure

Electron elastic scattering off a spin-polarized Cr atom

Electron elastic scattering off a spin-polarized Cr(...$3d^{5}4s^{1}$, $^{7}S$) atom is theoretically studied in the region of electron energies up to $15$ eV using both a one-electron "spin-polarized" Hartree-Fock and multielectron "spin-polarized" random phase approximation with exchange. It is found that scattering phase shifts of oppositely spin-polarized incoming electrons and corresponding cross sections of the scattering reactions significantly differ from each other, in general, even without accounting for spin-orbit interaction. This is shown to be associated with the presence of two semifilled $3d^{5}$ and $4s^{1}$ subshells in the Cr's configuration which induce considerably different exchange in the interaction of oppositely spin-polarized incoming electrons with the atom-target. The importance of electron correlation in $e^{-}+\rm Cr$ elastic scattering process is revealed. Moreover, correlation is shown to induce strong differences between scattering of oppositely spin-polarized electrons off Cr. A physically transparent interpretation for the latter is provided.Comment: 6 pages, 7 figures, submitted to Phys. Rev.