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Magnetisation of supported drug molecules and Electrification of solvated graphene from First-Principles - Marie-Laure Bocquet - Mardi 11 décembre 2018 à 11 h

INSP - Sorbonne Université - 4 place Jussieu - 75005 Paris - Barre 22-23, 3e étage, salle 317

Marie-Laure Bocquet - ENS, Laboratoire PASTEUR, Paris

Abstract

In this talk I will describe two recent examples that illustrate how quantum chemistry through static and dynamic approaches can decipher complex surface reactivities in close collaboration with dedicated experiments. These fundamental processes are key to advance and to promote sustainable routes for purely organic magnets in UHV and carbon-based desalinization membranes in water.

The first part deals with retinoid closed-shell molecules adsorbed on gold in UHV that exhibit a localized and long-lived spin after the STM manipulation with voltage pulses. [1] But the detailed mechanism of spin creation, localization and stabilization was missing. I will explain the probable mechanism at play that do recover the main characteristics of the imaging and spectroscopic data. [2]

The second part focuses on the recent emergence of nanofluidics that unveil a considerable but differential electrification of the graphene sheet and its twin fraternal twin – hexagonal boron nitride – when dipped into a salt electrolyte at various pH conditions. [3-4] This surface charging was conjectured to originate in the differential hydroxide adsorption at the surface of these twin materials, but no proof has been given until now. I will present our recent ab initio molecular dynamics simulations of hydroxide OH- ions in water near graphene and hexagonal boron nitride (h-BN) layers that provide unexpected behaviors. [5]

[1] S. Karan, N. Li, Y. Zhang, Y. He, I. P. Hong, H.Song, J.-T. Lü, Y. Wang, L. Peng, K. Wu, G. S. Michelitsch, R. J. Maurer, K. Diller, K. Reuter, A. Weismann, R. Berndt, Physical Review Letters 2016, 116, 027201.

[2] M.-L. Bocquet, N. Lorente, R. Berndt, M. Gruber, Angew. Chem. Int. Ed. 10.1002/anie.201812121.

[3] A. Siria, P. Poncharal, A.-L. Biance, R. Fulcrand, X. Blase, S. T. Purcell, and L. Bocquet, Nature 494, 455 2013. [4] E. Secchi, A. Niguès, L. Jubin, A. Siria, and L. Bocquet, Physical Review Letters 2016, 116, 154501.

[5] B. Grosjean, M.-L. Bocquet, and R. Vuilleumier, submitted.