Ab initio description of optical nonlinearities induced by impulsive broadband radiation (INPULS)

• Applicant: Professorin Dr. Caterina Cocchi
• Subject Area: Theoretical Condensed Matter Physics
• Term: since 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 524452181

The theoretical description of optical limiting (OL) in molecules is still in its infancy, despite the popularity gained by first-principles methods in the characterization of spectroscopic properties in these systems. Established methods based on model Hamiltonians have proven to be very effective to reproduce experimental trends. However, their dependence on empirical parameters limits dramatically their applicability to unknown compounds. The first development of an ab initio scheme for OL based on real-time time-dependent density-functional theory (RT-TDDFT), proposed by the applicant and her coworkers in 2014, has paved the way to a non-perturbative, parameter-free description of this phenomenon at affordable computational costs. However, the variety and complexity of the mechanisms contributing to OL call for dedicated analysis and further developments which are at the core of this project. Herein, we aim to develop an efficient and accurate first-principles scheme based on RT-TDDFT to predict, describe, and interpret OL and related optical nonlinearities in organic molecules. We plan to extend our seed approach to (i) identify the driving mechanisms of OL; (ii) account for the effects of electron-vibrational interactions; (iii) include in the method electrostatic coupling with the environment. Direct comparison with experiments performed by an external project partner is envisioned as a quantitative point of reference for our results. The inclusion of the developed method into an automated workflow will enable its dissemination also beyond the theorists’ community.

• DFG Programme: Research Grants
• International Connection: Italy
• Cooperation Partner: Dr. Carlo Andrea Rozzi