arXiv subjects

Rasheed Shaik

Publications and source records attributed to Rasheed Shaik.

4 recordsLinked to original sources

arXiv2024

Hybridization and coherence in subshell differential intercluster plasmonic decay in $Na_{20}@C_{240}$

We study the ground state structure and aspects of photoionization dynamics of the $Na_{20}@C_{240}$ endofullerene. The structure shows effects from the electronic coupling between the nested cluster and the fullerene cage. They include the (i) alterations of the overall potential, and thus, the force field, (ii) electron transfer from the cluster to the fullerene forming ionic units, and (iii) hybridization from the admixture of free $Na_{20}$ occupied levels with experimentally known super-atom molecular orbital (SAMO) type empty levels of $C_{240}$ accessible in the jellium-DFT model. These modifications influence the photoionization dynamics of the endofullerene. For the high energy ionization of $Na_{20}$-type levels, a significant overall enhancement of the cross section is noted from additional ionizing force that $C_{240}$ offers. More remarkably, the photoexcited plasmons, both the giant plasmon and the higher energy plasmon, in decay in parts through $Na_{20}$ ionization continuum via the resonant intercluster Coulombic decay (ICD) process. These lead to dramatic enhancements in the ionization of individual $Na_{20}$-type levels resulting enhancements in the cluster's total ionization yield. Based on hybridization, this enhancement incorporates a coherent mixing of the ICD and SAMO-induced Auger-decay amplitude, in which the ICD contribution is dominant.

physics.atm-clus↗

arXiv2024

Simultaneous real and momentum space electron diffraction from a fullerene molecule

Plane-wave electrons undergo momentum transfer as they scatter off a target in overlapping spherical waves. The transferred momentum leads to target structural information to be encoded in angle and energy differential scattering. For symmetric, periodic or structured targets this can engender diffraction in the electron intensity both in real (angular) and in momentum space. With the example of elastic scattering from C60 we show this simultaneous manifestation of diffraction signatures. The simulated angle-momentum diffractograms can be imaged in experiments with a two-dimensional detector and an energy-tunable electron gun. The result may inspire invention of technology to extend scopes of electron diffraction from molecules and nanostructures, open a direction of electron crystallography using the momentum-differential diffraction, and motivate an approach to control the time delay between the pump laser-pulse and the probe electron-pulse by tuning the electron impact-speed in ultrafast electron diffraction experiments.

physics.atm-clus↗

arXiv2024

EWS time delay in low energy e C60 elastic scattering

Time delay in a projectile-target scattering is a fundamental tool in understanding their interactions by probing the temporal domain. The present study focuses on computing and analyzing the Eisenbud-Wigner-Smith (EWS) time delay in low energy elastic e C60 scattering. The investigation is carried out in the framework of a non-relativistic partial wave analysis (PWA) technique. The projectile-target interaction is described in (1) Density Functional Theory (DFT) and (2) Annular Square Well (ASW) static model, and their final results are compared in details. The impact of polarization on resonant and non-resonant time delay is also investigated.

math.NA↗

arXiv2022

Plasmonic Resonant Intercluster Coulombic Decay

Light-induced energy confinement in nanoclusters via plasmon excitations influences applications in nanophotonics, photocatalysis, and the design of controlled slow electron sources. The resonant decay of these excitations through the cluster's ionization continuum provides a unique probe of the collective electronic behavior. However, the transfer of a part of this decay amplitude to the continuum of a second conjugated cluster may offer control and efficacy in sharing the energy nonlocally to instigate remote collective events. With the example of a spherically nested dimer Na20@C240 of two plasmonic systems we find that such a transfer is possible through the resonant intercluster Coulomb decay (RICD) as a fundamental process. This plasmonic RICD signal can be experimentally detected by the photoelectron velocity map imaging technique.

physics.atm-clus↗