A theoretical investigation of elastic scattering of H atom by C₆₀ and Kr@C₆₀

Abstract

We report an extensive study of cross section, phase shift and time delay for H–Kr@C60 elastic scattering. To demonstrate the effect of encapsulation, we extend this study to H–C60 elastic scattering also. Interaction potential is calculated using density functional theory for the scattering through both hexagonal and pentagonal rings of bare C60 and Kr@C60. The interaction potential for H–C60 is a double-humped barrier. In H–Kr@C60 case, this interaction has an additional huge core repulsive region near the center of C60, which is due to presence of the encapsulated atom. The scattering cross section exhibits glory oscillations and resonances, which are qualitatively different for the scattering through pentagonal and hexagonal rings of C60. The observed resonances arise due to combined effect of centrifugal and C60 potential barrier. We notice bunching of phase shifts for even–even and odd–odd ℓ partial waves in H–C60 scattering, consequently this happens in all measured scattering observables. The presence of the confined atom eliminates this phase bunching; therefore, H–Kr@C60 scattering rather gives well-organized and sequential placement of resonances in order of ℓ values.

Effect of charge transfer on elastic scattering of electron from Ar@C60: Dirac partial wave calculation

“…Although the ASW model is capable of simulating major effects of confinement, the model lacks diffuseness at the boundaries of the C 60 shell. Because of the unphysical hard boundaries of the ASW model, several alternate model potentials have been proposed such as δ-potential [16], Gaussian model [37], Gaussian annular square well (GASW) potential [38], power exponential model [39], the combination of Woods-Saxon (W-S) potentials [30], Lorentz function model [40], and potential derived from DFT calculations [41,42], etc. The choice between diffuse and hard confinement potentials for the C 60 continues to be a subject of debate [30,31,38,42,43].…”

“…Because of the unphysical hard boundaries of the ASW model, several alternate model potentials have been proposed such as δ-potential [16], Gaussian model [37], Gaussian annular square well (GASW) potential [38], power exponential model [39], the combination of Woods-Saxon (W-S) potentials [30], Lorentz function model [40], and potential derived from DFT calculations [41,42], etc. The choice between diffuse and hard confinement potentials for the C 60 continues to be a subject of debate [30,31,38,42,43]. The present work aims to showcase the sensitivity of e-C 60 and e-A@C 60 scattering to the nature of the confinement potentials employing the ASW and GASW model potentials.…”

Elastic electron scattering from A@C n (A = Ca, Mg, n = 60, 20)

“…Endohedral fullerene A@C N , where an atom A is encapsulated inside the interior of fullerene cage, has drawn considerable interest of investigators both to the basic and applied sciences and technologies [1,2]. Effective methods to study such confined atoms are photoionization [3][4][5] and elastic scattering [6,7]. It has been rather difficult to perform such experiments due to the difficulty to produce sufficient amount of purified doped fullerenes in past decades, the situation becomes much better now [8][9][10][11][12].…”

Ab initio calculation of electrostatic potentials for C60 and C80

“…Endohedral fullerenes, A@C 60 , where an atom or small molecule is embedded inside the fullerene, have attracted considerable interest in recent years [1][2][3]. Effective experimental methods to study such confined atoms are photoionization [4][5][6] and elastic scattering [7,8]. Confinement resonances produced in the photoionization of Xe@C 60 have been demonstrated in the notable breakthrough experiment by Kilcoyne and co-workers [4,5].…”