Confinement resonances

Photoionization of doped fullerene anions Coulomb confinement resonances 38... 

The dependence of confinement resonances on quantum numbers of the ionized subshell nl can be illustrated by the 5-potential model calculated data [34] for the Ne Is and 2s photoionization cross sections from Ne C60, see Figure 5. 

Mb. Note, also, that, away from the threshold, the confinement resonances in er1 <5 and a s emerge at different energies and have different resonance amplitudes. Caution since the data displayed in Figure 5 were obtained in the 5-potential model, the predicted amplitudes of confinement resonances in these photoionization cross sections are, most likely, overestimated, as in the case of Xe C60-... 

Both models demonstrate sizable oscillations, i.e., confinement resonances, in the energy dependence of photoelectron angular distribution parameters. The resonances fade away rapidly with an increasing energy of the photoelectrons. The decrease in the resonance amplitudes with increasing... 

The discovery of confinement resonances in the photoelectron angular distribution parameters from encaged atoms may shed light [36] on the origin of anomalously high values of the nondipole asymmetry parameters observed in diatomic molecules [62]. Following [36], consider photoionization of an inner subshell of the atom A in a diatomic molecule AB in the gas phase, i.e., with random orientation of the molecular axis relative to the polarization vector of the radiation. The atom B remains neutral in this process and is arbitrarily located on the sphere with its center at the nucleus of the atom A with radius equal to the interatomic distance in this molecule. To the lowest order, the effect of the atom B on the photoionization parameters can be approximated by the introduction of a spherically symmetric potential that represents the atom B smeared over... 

In this case, the photoionization cross section possesses no Coulomb confinement resonances. This is because the fullerene cation s potential Vcti(r) seen by an outgoing photoelectron does not exhibit a Coulomb potential barrier (see Figure 10 for z = +5 for illustration purposes). 

The above discussion was focused on confinement resonances, whether regular or Coulomb, in the photoionization spectra of atoms encaged in a neutral or charged C60 carbon cage. 

The confinement resonance pattern in y (co) generally displays the same trends as in a A(co). In particular, an increasing size of a carbon cage increases the number, sharpness, and amplitudes of the confinement resonances in for single-walled fullerenes, whereas... 

Looking at the calculated results for y A( >), a natural question arises how differently confinement resonances show up in dipole photoionization... 

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