Following the steps of a chemical reaction or a 2D phase transition by scanning tunneling microscopy

DIPC Seminars

Speaker

Rolf Moeller, Fakultaet fuer Physik, Universitaet Duisburg-Essen, Germany

When

2019/05/03
14:00

Place

Donostia International Physics Center

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In most cases, it is not possible to follow the reaction of an individual molecule in real space and time. For the example of the dehydrogenation and dechlorination of a porphyrine molecule (octaethylporphyrin Fe(III) chloride (FeOEP-Cl) ) on Cu(111) the complete pathway of the reaction with 16 inequivalent intermediate states and the rates of the involved processes are revealed. This is achieved by combining the analysis of a large data set showing thousands of molecules in the different stages of the reaction with numerical simulations. In the second part a reversible structural phase transition of a two dimensional system which can be locally induced by an external electric field will be discussed. The balance between two coexisting phases of Co on Cu(111) can be shifted by an external electric field, causing the domain boundaries to move, increasing the area of the favored phase controllable both in location and size. If the field is further enhanced new domains nucleate. The arrangement of the CO molecules on the Cu surface is observed in real time and real space with atomic resolution while the electric field driving the phase transition is easily varied over a broad range. Host: Nacho Pascual