Spring '23 Department Seminars with Dr. Fahri Alkan

Title: Approximate TDDFT Methods for the Optical Properties of Metal Nanoclusters

Speaker: Dr. Fahri Alkan

Department of Nanotechnology Engineering, Abdullah Gül University

Kayseri, Türkiye

Date: April 3, 2023, Tuesday

Time: 12:30

Place: SB-Z14


Linear-response time dependent density functional theory (LR-TDDFT) has been the workforce of quantum chemistry for the computation of excited-states and theoretical analysis of optical and photophysical properties for molecular systems. In that aspect, LR-TDDFT has also been employed to metal nanoclusters and model nanoparticles, especially in systems where quantum mechanical and atomistic effects become crucial for accurate description of optical properties. However, one main drawback of LR-TDDFT is that it becomes computationally intensive as the system of interest approaches to ~1000 atoms, a limit that can be easily exceeded for theoretical treatment of nanomaterials.

In this talk, we will explore the applications of LR-TDDFT, along with alternative approximate-TDDFT formalisms for efficient predictions of photophysical properties for metal nanoparticles and clusters. In the first part, my focus will be on the plasmonic interaction and its description within different TDDFT formalisms. In addition, some recent work with approximate real-time approaches will also be presented for plasmon coupling with a focus on the size and orientation dependence of such interactions. In the second part, I will discuss the use of approximate-TDDFT methods for case studies involving atomically-precise metal nanoclusters. In particular, effect of the ligand shell composition and electronic structure on the photophysical properties and chiral activity will be explored for such systems.

Short Biography of the Speaker:

Fahri Alkan received his B.Sc and M.Sc. in Chemistry at Bilkent University. He obtained his Ph.D. in physical chemistry from University of Delaware (2016) under the supervision of Prof. Cecil Dybowski. His Ph.D. studies involved computation of NMR parameters for heavy-metal nuclei such as 207Pb and 199Hg using relativistic DFT methods. He then worked as a postdoctoral research associate at Kansas State University (2016-2019) with Prof. Christine Aikens. Starting from 2019, he has been working as a faculty member at the Materials Science and Nanotechnology Engineering Department of Abdullah Gül University. His research interest mainly involves theoretical description of light-matter interactions and excited-state dynamics of metal nanoclusters and molecular fluorophores.