What can we learn from single-molecule chemistry?
소속 :
연사 : Prof. Yousoo Kim ( RIKEN)
일시 : 2012-06-04 16:00 ~
장소 : 503동 404호
일 시 : 2012년 6월 4일, 4:00 PM
장 소 : 503동 404호
-Abstract-
The study of single molecules provides deep insights into a bonding nature and underlying quantum mechanics concerning about understanding and controlling chemical reaction. The scanning tunneling microscope (STM) is a versatile and powerful tool for investigating and controlling chemistry of individual molecules on the solid surfaces. The coupling of tunneling electrons to the electronic and vibrational states of the target molecule allows us to realize mode-selective and state-selective chemistry of the individual molecules.
In this talk, I will address two main issues with our experimental and theoretical efforts on investigating interaction of electrons with vibrational and electronic states of a single molecule on the surfaces. The first part is assigned to the excitation of vibrational modes to selectively induce particular dynamic motion and chemical reaction of a single molecule on the metal surfaces. The microscopic mechanism of vibrationally induced molecular motions and the selection rules for the single-molecule vibrational spectroscopy are also discussed. The second part focuses on the selective control of reaction pathways by use of long lifetime of vibrationally and electronically excited states of a molecule on an ultrathin insulating metal oxide surface. The theoretical study revealed that the presence of O vacancies or Mg interstitials at the interface between MgO ultrathin film and Ag(100) substrate result in a substantially lower barrier for the dissociation of water. In the presence of these defects, the chemical reactivity of the film is greatly enhanced. In this respect, this study suggests a route to modify the chemical properties of the film surface.
장 소 : 503동 404호
-Abstract-
The study of single molecules provides deep insights into a bonding nature and underlying quantum mechanics concerning about understanding and controlling chemical reaction. The scanning tunneling microscope (STM) is a versatile and powerful tool for investigating and controlling chemistry of individual molecules on the solid surfaces. The coupling of tunneling electrons to the electronic and vibrational states of the target molecule allows us to realize mode-selective and state-selective chemistry of the individual molecules.
In this talk, I will address two main issues with our experimental and theoretical efforts on investigating interaction of electrons with vibrational and electronic states of a single molecule on the surfaces. The first part is assigned to the excitation of vibrational modes to selectively induce particular dynamic motion and chemical reaction of a single molecule on the metal surfaces. The microscopic mechanism of vibrationally induced molecular motions and the selection rules for the single-molecule vibrational spectroscopy are also discussed. The second part focuses on the selective control of reaction pathways by use of long lifetime of vibrationally and electronically excited states of a molecule on an ultrathin insulating metal oxide surface. The theoretical study revealed that the presence of O vacancies or Mg interstitials at the interface between MgO ultrathin film and Ag(100) substrate result in a substantially lower barrier for the dissociation of water. In the presence of these defects, the chemical reactivity of the film is greatly enhanced. In this respect, this study suggests a route to modify the chemical properties of the film surface.
