Modeling of high harmonic generation in the C\textsubscript{60} fullerene using \textit{ab initio}, DFT-based and semiempirical methods

Abstract: We report calculations of the high harmonic generation spectra of the C\textsubscript{60} fullerene molecule, employing a diverse set of real-time time-dependent quantum chemical methods. All methodologies involve expanding the propagated electronic wavefunction in bases consisting of the ground and singly excited time-independent eigenstates obtained through the solution of the corresponding linear-response equations. We identify the correlation and exchange effect in the spectra by comparing the results from methods relying on the Hartree-Fock reference determinant with those obtained using approaches based on the density functional theory with different exchange-correlation functionals. The effect of the full random phase approximation treatment of the excited electronic states is also analyzed and compared with the configuration interaction singles and the Tamm-Dancoff approximation. We also showcase that the real-time extension of the semiempirical method INDO/S can be effectively applied for an approximate description of laser-driven dynamics in large systems.