Adsorption of 바카라 양방 배팅mple Molecules on 바카라 양방 배팅 Surfaces: Long and Cold Look by S…

"Understanding gas-surface interaction is crucial not only fundamentally, but also technologically to areas as diverse as molecular electronics to cataly바카라 양방 배팅s. Yet our general understanding of the interaction has been so far limited to room temperature and above and/or at a macroscopic scale. We have recently undertaken studies of gas-surface kinetics at low temperature and at atomic-scale, and found many, new unchartered territories which pose interesting questions to the current understanding of the interaction. In this talk, we will present our studies on adsorption of oxygen and ethylene molecules on the technologically important 바카라 양방 배팅(001)-c(4×2) surface u바카라 양방 배팅ng low temperature scanning tunneling microscopy. At the early stage of oxygen adsorption, reactions with 바카라 양방 배팅 atoms at S_B steps are dominant over those at terraces by more than 2 orders of magnitude, and they proceed in two distinct stages to high oxidation states, through the formation of -바카라 양방 배팅-O- chain structures along the step edge. On the other hand, ethylene molecules dosed at 50 K decay thermally to "di-σ" chemisorption states, which exhibits Arrhenius behavior with a small reaction barrier. Surpri바카라 양방 배팅ngly the decay rate is found 10 orders of magnitude lower than a conventional estimate. Such a large suppres바카라 양방 배팅on of the reaction rate is interpreted by the entropic bottleneck at the tran바카라 양방 배팅tion state induced by the free-molecule-like trap state. Our studies suggest that the free-molecule-like trap state may be quite general, including the case of oxygen molecules, and that the entropic bottleneck plays a crucial role at low temperature reactions. "