Northwestern 대학의 이론화학자인 George Schatz가 대한화학회 일로 한국을 방문하는 기회에 서울대학교에서 세미나를 합니다. 실험하는 사람들이 관심있어 하는 "실제적인" 문제에 대해서 이론/계산을 하는 사람입니다. 좋은 기회입니다. 한 번 가서 들어봅시다.
1. 일시: 2014년 4월 21일(월) 오후 4:30
2. 장소: 25-1동 103호 국제회의실
3. 연사: Prof. George C. Schatz (Department of Chemistry, Northwestern University)
4. 제목: Molecular Plasmonics
This talk describes recent theory developments concerned with the optical properties of plasmonic materials, with emphasis on understanding plasmon enhanced spectroscopic techniques such as SERS, plasmon-enhanced photochemistry, and the coupling of plasmons to excitons. The cornerstone of this work is computational electromagnetics, which provides the ability to solve Maxwell’s equations exactly for a given nanoparticle structure and with assumed dielectric functions. A number of methods for doing these calculations are available, and in the first part of the talk we show how one can use them to study important problems of interest in plasmonics. These applications show how small gaps (1 nm) between 100 nm silver or gold nanoparticles lead to electromagnetic hot spots with multipole plasmon modes that produce the largest SERS enhancements when dark plasmon modes are excited, in part due to excitation of the dark modes by Raman emission. This application shows that classical electrodynamics needs to be coupled to quantum mechanics for a quantitative description of SERS, so the second half of the talk will focus on methods that couple electrodynamics calculations with TDDFT either in real-time or with frequency domain calculations. Inclusion of both electromagnetic interactions and chemical interactions between the metal nanoparticle and molecular adsorbate are considered. We demonstrate the use of these QM/ED methods with applications to SERS and to plasmonic solar cells. In addition, we describe several examples of plasmon-exciton interactions, such as occurs in plasmon-enhanced lasing. Here we show how plasmons can interact with molecules to enhance both spontaneous and stimulated emission.