A unique situation for an endohedral metallofullerene

Abstract

This letter demonstrates for the first time that an endohedral environment, such as the bucky-ball C 60 , can produce a significant redistribution of oscillator strengths in endohedrally trapped atoms, making the dominant transitions no longer superior but inferior, and also making electron correlations in such atoms act in an opposite way to free atoms. This is exemplified by calculations of the oscillator strengths and photoionization cross sections of the Ca atom trapped inside C 60 . Also, while photoionization cross sections can undergo dramatic changes on confinement, the photoelectron angular asymmetry parameter β n can, in contrast to natural expectation, remain largely unchanged. The random-phase approximation with exchange was employed. We believe these are the first calculations of electron correlations for confined atomic species.

Interchannel coupling effects on non-dipole photoionization parameters

“…Calcium in a fullerene cage ðCa @ C 60 Þ has been considered for such studies. Only non-relativistic many-body formalism has been used so far, and studies have been carried out only in the dipole approximation (Connerade et al, 1999). We present below our investigations on endohedrally confined calcium by using RRPA and report the angular distribution of photoelectrons, inclusive of (E1, E2) interference effects.…”

“…Also, we report on the angular distribution asymmetry parameters with the inclusion of non-dipole terms for a confined atom, generally denoted by @ X where X is the atom in a confining potential. We have examined the case of @ Ca (Connerade et al, 1999) as a model system for this study. Our results show that in @ Ca the non-dipole effects become dramatically enhanced due to confinement.…”

Calculated Electronic Behavior and Spectrum of Mg+@C60 Using a Simple Jellium-shell Model

“…The encapsulating ("confining") cage is approximated as a spherical square well [8][9][10][11]16] and has the functional form…”

“…The well depth is adjusted so that the model reproduces the electronic behavior of a single electron in the jellium shell as calculated from first principles [8] or the photoionization behavior of other caged species. [9][10][11]16] We chose the latter parameters due to the similarity of the models involved. Now Equation (3) must be discretized in order to pursue a numerical solution.…”

“…Such models have been utilized to calculate the photoabsorption spectrum of C 60 as well as that for endohedral Xe and Ba [7]. In addition, the jellium-shell model has been used to reproduce certain aspects of the photoionization cross section of C 60 [8] and it has been successfully applied to other endohedral Fullerene systems [9][10][11].…”