Time delay in XUV photon driven ionization of C₆₀ giant plasmon

Large scale coherent electron correlations play the dominant role to induce a giant plasmon excitation in fullerenes driven by extreme ultra-violet (XUV) light absorption. This excitation primarily decays via the single-electron continuum channels to create a broad resonance in the ionization spectrum. The underlying many-body mechanism induces a temporary attractive force to affect the time delay of the photoelectrons to reach the detector. In order to determine this delay, the so-called Eisenbud-Wigner-Smith delay, for the C₆₀ fullerene molecule, we apply a scheme of linear response time-dependent density functional theory [1] where the C₆₀ ion-core is frozen in a spherical jellium charge distribution. We find a delay approximately within the range of 100-200 attoseconds over the plasmon resonance energy range. This is comparable to the average dephasing time obtained from the linewidth of the resonance. The result served as an essential ingredient to describe recent real time measurements by photoelectron chronoscopy [2]. [1] Choi et al., Phys. Rev. A, 95, 023404 (2017); [2] Biswas et al., arXiv:2111.14464 [physics.atom-ph]