Impact spectroscopy of fullerene molecules: diffraction, plasmon excitation and time-delay

Remarkable symmetry and broad application landscape render fullerene molecules important for spectroscopic studies. Such studies include impact by electrons leading to scattering or by positrons forming electron-positron binaries, the positroniums [1]. They also include interactions with photons driving plasmon excitations, which subsequently decay by emitting photoelectrons. In the momentum distribution of scattered electrons and positroniums or often in photoelectron spectral lines the signature of diffraction is ubiquitous. Moreover, for scattered electrons and positronium the diffraction can also be seen in real (angular) space [2]. In particle collisions, such 2D diffraction mechanisms may extend the ability and scope of ultrafast diffraction measurements. For the photon impact studies the ultrafast (in attoseconds) dynamics of photoelectron production mechanism is accessible. Within an appropriate energy range of extreme UV pulsed photons, the electrons in fullerenes can be instantly excited to a plasmonic state where they are transiently trapped until the plasmon de-phases. This leads to the electrons’ delayed emergence in the continuum and this delay can be measured by, for instance, streaking with a near IR probe pulse, and the entire process can be simulated for comparison [3]. For a fullerene conjugated with another plasmonic system, transfer of fullerene plasmon energy to excite quiescent electrons of the other system via inter-Coulombic decay (ICD) route is also possible [4]. In this talk, I will present some of our recent computational studies across these processes.

References:

[1] P-A Hervieux, A.R. Chakraborty, and H.S. Chakraborty, Ubiquitous diffraction resonances in positronium formation from fullerenes, Phys. Rev. A Rapid Comm. 95, 020701 (R) (2017).

[2] Aiswarya R., R. Shaik, J. Jose, H.R. Varma, and H.S. Chakraborty, Simultaneous real and momentum space electron diffraction from a fullerene molecule, in preparation.

[3] S. Biswas et al, Attosecond correlated electron dynamics at C₆₀ giant plasmon resonance, Preprint: http://arxiv.org/abs/2111.14464.

[4] R. Shaik, H.R. Varma, M.E. Madjet, F. Zheng, T. Frauenheim, and H.S. Chakraborty, Plasmonic resonant intercluster Coulombic decay, Phys. Rev. Lett. 130, 233201 (2023).