| 研究実績の概要 |
We have studied the adsorption of meso-dibenzoporphycene (mDBPc) on several metallic surfaces to try to characterize the tautomerization reaction of this molecule in the presence of a substrate. We have found difficulties to identify the cis- and trans-configurations of the molecule with conventional imaging. To overcome this difficulty, we have tried more sophisticated experimental imaging methods, such as Kelvin probe force microscopy and constant-height intramolecular-resolution imaging with carbon monoxide functionalized probes, on mDBPc molecules deposited on a sodium chloride (NaCl) thin-film substrate. We have identified two configurations of the molecule on these insulating films, one asymmetric and parallel to the NaCl lattice, and the other symmetric with the long axis of the molecule rotated 45° from the NaCl lattice. We have induced the flipping of the molecule for the asymmetric configuration by setting an appropriate bias, however, the appearance of the molecule after the flipping is a mirror image of the previous configuration. Our experiments point towards an energy adsorption landscape where one of the configurations of the molecule has a dominant energy potential well with respect to the other. The assignation of this more estable configuration to either cis- or trans- is currently carried out by the compassion of experimental intramolecular resolution images with computer-simulated atomic force microscopy images of the most stable adsorption configuration obtained from first-principles calculations.
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