Ultrafast Phenomena Never Seen Before

Abstract: 

With the aid of our new quantum chemical theory, MRSF-TDDFT¹, various aspects of excited processes have been explored within the framework of nonadiabatic molecular dynamics (NAMD). Investigating sub-picosecond (sub-ps) dynamics is particularly challenging for experimental techniques, making theoretical studies invaluable. For instance, the unique bond-alternation damping dynamics in Dihydro-Azulene in ~ 200 fs have been shown to directly evidence the excited state aromatization process. In uracil, the hydrogen out-of-plane bending motion in ~ 140 fs can lead to the formation of an unexpected new species, potentially responsible for hydration and the primary photo-damage process causing nucleobase photo-instability. Additionally, a novel pendulum-like dynamics of the terminal group in Green Fluorescence Protein (GFP) was observed, which acts as a controller for fluorescence intensity. 

These examples underscore the significance of ultrafast dynamics occurring in sub-ps timescales, where coherent direct vibronic couplings play a decisive role in determining the fate of excited states. In this talk, I will provide a brief introduction to MRSF-TDDFT, followed by a discussion of its various applications.

¹Park, W., Komarov, K., Lee, S., & Choi, C. H. (2023). Mixed-Reference Spin-Flip Time-Dependent Density Functional Theory: Multireference Advantages with the Practicality of Linear Response Theory. The Journal of Physical Chemistry Letters (Perspective), 14(39), 8896-8908. 

20240530_대학원세미나_최철호 교수.pdf