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

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. (paper)