Nonlinear Molecular Electronic Spectroscopy via MCTDH Quantum Dynamics: From Exact to Approximate Expressions

• DOI: 10.1021/acs.jctc.2c01059
• Publication Date: 2023-03-24T18:45:20Z
• Authors: Francesco Segatta; Daniel Aranda Ruiz; Flavia Aleotti; Martha Yaghoubi; Shaul Mukamel; Marco Garavelli; Fabrizio Santoro; Artur Nenov
• Keywords: Hartree; Dephasing; Vibronic coupling; Hamiltonian (control theory)

We present an accurate and efficient approach to computing the linear nonlinear optical spectroscopy of a closed quantum system subject impulsive interactions with incident electromagnetic field. It incorporates effect ultrafast nonadiabatic dynamics by means explicit numerical propagation nuclear wave packet. The fundamental expressions for evaluation first- higher-order response functions are recast in general form that can be used any code capable overlap packets evolving different states. Here we these multiconfiguration time-dependent Hartree (MCTDH) method. Application is made pyrene, excited its lowest bright state S2 which exhibits sub-100-fs decay dark S1. described vibronic coupling Hamiltonian, parametrized electronic structure methods. show have remarkable on spectral line shapes goes beyond simple lifetime broadening. Furthermore, widely employed approximate expression based time scale separation dephasing population relaxation same theoretical framework. pyrene shows range validity such approximations.