Single molecules at the atomic scale: excitons and trions, circumstellar analogues and on-surface catalysis
par Pablo Merino
Material Science Institute of Madrid (ICMM-CSIC)
Mardi 11 février, 11h – Amphithéâtre de l’ISMO
Scanning probe microscopies (SPM) under ultrahigh vacuum and cryogenic conditions enables exploration of the relations between the adsorption geometry, electronic state, and spectroscopic fingerprints with a ground-breaking atomistic perspective. SPMs allow to visualize in real space the properties of individual quantum systems one-by-one. This is crucial advantage for studying emerging phenomena that usually become obscured in ensemble measurements. In this talk, I will present results where submolecular precision has been instrumental in untangling the origin of complex systems. Astrochemical analogues —molecular products generated in physicochemical conditions mimicking interstellar and circumstellar environments— are usually a mixture of different molecular species. Using SPM, we identified the products of our astrophysical simulations as primarily consisting of aliphatic materials. [1,2] Furthermore, I will discuss how SPM allowed us to trace the dehydrogenation of single aliphatic molecules on catalytic surfaces, revealing the cascade of catalytic reactions that are challenging to resolve using conventional methodologies. [3] At last, I will show how the integration of SPMs with optical spectroscopies permits to visualize excitonic and Raman processes below the diffraction limit, highlighting how emission and scattering depend on the molecular geometry and the precise charge state. [4,5]
References
[1] L Martínez, et al., Nature Astronomy 4 (1), 97-105 (2020)
[2] P. Merino et al., Communications Chemistry 7 (1), 165 (2024)
[3] D. Arribas, et al., Nanoscale 15 (35), 14458-14467 (2023)
[4] K Kuhnke, C Grosse, P Merino, K Kern, Chemical reviews 117 (7), 5174-5222 (2017)
[5] R.C. Campos Ferreira et al., ACS Nano, 18, 13164-13160 (2024)