121st General Meeting of the KCS

Type Poster Presentation
Area Physical Chemistry
Room No. Event Hall
Time 4월 20일 (금요일) 11:00~12:30
Code PHYS.P-225
Subject Molecules in the intramolecular charge transfer states probed by ultrafast vibrational spectroscopy
Authors Sebok Lee, Myungsam Jen, kooknam jeon, JOONWOO KIM, YOONSOO PANG*
Department of Chemistry, Gwangju Institute of Science and Technology, Korea
Abstract Intramolecular charge transfer (ICT) reaction has been of great interest in chemistry and related disciplines due to potential applications to chemical reaction control, molecular electronics, etc.. Femtosecond time-resolved spectroscopy has been successfully adopted to investigate the dynamics of the ICT process usually occurring in sub-picosecond time scales. Numerous experimental and theoretical investigations on the structural nature of the ICT state of a laser dye DCM, for example still leaves an unfinished debates on the geometry of "twisted" vs. "planar". Femtosecond stimulated Raman spectroscopy with both high temporal (<50 fs) and spectral (<10 cm-1) resolutions may be able to answer this question on the charge transfer state. In this work, the structural changes accompanying the ICT process in many dyes with both electron donating and accepting groups have been investigated and the ICT process of DCM occurring within ~1 ps and being followed by vibrational relaxation of ~5 ps was evidenced by the population changes and frequency shifts of many excited state Raman bands including ν(C≡N), δ(C=C/C-C), and δ(CH3). The changes in the ICT dynamics due to small perturbations in the molecular structure of electron donator or acceptor have also been investigated and theoretical investigation by the TDDFT simulations will also be added to widen our understand on the ICT state.
E-mail leesebok@gist.ac.kr