2018/09/09 by Dolmatov, V. K.
#Atomic Physics (physics.atom-ph) #FOS: Physical sciences
paper · doi:10.48550/arxiv.1809.02898
Photoionization cross sections, photoelectron angular-asymmetry parameters and photoionization time delays for A@C60 endohedral atoms are studied with account for both the individual and combined effects of dipole static polarization (DSP) of C60 by the outgoing photoelectron, interior static polarization (ISP) of C60 by the ion-remainder, A+, and atomic-core relaxation of the encapsulated atom upon its ionization. It is unraveled that the DSP effect is weak; it changes the phase of confinement-resonant oscillations in σnℓ, βnℓ and τnℓ without generally noticeable changes in their magnitudes, unless σnℓ concentrates a relatively large part of oscillator strength of the continuum spectrum near threshold. This is counter-intuitive in view of a large dipole static polarizability of C60, α> 800 a.u.. Furthermore, it is demonstrated that the DSP effect results in the transmission of a part of oscillator strength of the continuum spectrum of A@C60 into its discrete spectrum. It is shown that the DSP effect is counteracted by ISP. Possible reasons behind the made findings are provided. Photoionization of Xe@C60, Ne@C60, H@C60 and some hypothetical C-60 fullerene anions is chosen as a case study. For Xe@C60, the role of atomic-core relaxation of the ionized encapsuled Xe+-ion-remainder on the \rm 4d photoionization of Xe@C60 is revealed to be of utter significance, as in free Xe. The random phase approximation with exchange (RPAE) and generalized RPAE were used in the study. The C60 cage is modelled by a spherical attractive potential of a certain inner radius, thickness and depth. Its dipole static polarization potential is approximated by the Bates dipole static potential.