Pushing back the boundaries for the atomistic simulation of electronic and ionic transport processes

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• Professor Jochen Blumberger, UCL
• Wednesday 19 March 2025, 14:30-15:30
• Unilever Lecture Theatre, Yusuf Hamied Department of Chemistry.

If you have a question about this talk, please contact Lisa Masters.

The last decades have witnessed tremendous progress in Theoretical and Computational Chemistry. Development of ever more ingenious algorithms have allowed us to solve some of the most fundamental equations governing chemical processes at steadily improved accuracy or for larger systems/longer time scales. As a result, Computational Chemistry has now penetrated many disciplines of the Natural Sciences and Engineering including Material and Energy Science, Catalysis and Chemical Biology. In my talk I will survey a number of recent studies where our group has contributed to this endeavour. In the first part of my talk I will describe how we pushed mixed quantum-classical non-adiabatic molecular dynamics from the molecular to the true nanoscale (10-100 nm) revealing a new transport mechanism, transient quantum delocalization, of charge carriers[1,2] and excitons³ in organic photovoltaic and thermoelectric materials.[4] In the second part of my talk I will describe a machine learning method that we have recently developed to simulate condensed phase systems interacting with an external electric field, termed perturbed neural network potential molecular dynamics (PNNP-MD).[5] We find that PNNP -MD accurately describes the dielectric properties of liquid water, specifically the field-induced relaxation dynamics, the dielectric constant, the field-dependent IR spectrum⁵ and ionic conductivites⁶ up to surprisingly high field strengths of about 0.2 V/Angstrom with little loss in accuracy when compared to ab-initio molecular dynamics. Going forward, we expect PNNP to give vital atomistic insight into myriad processes, ranging from ionic conduction in electrolytes to field-directed catalysis to electrochemical energy conversion.

References:

[1] S. Giannini, A. Carof, M. Ellis, H. Yang, O. G. Ziogos, S. Ghosh, and J. Blumberger, “Quantum localization and delocalization of charge carriers in organic semiconducting crystals,” Nat. Commun., vol. 10, p. 3843, 2019. Geerts, F. Schreiber, G. Schweicher, H. Wang, J. Blumberger, M. Bonn, and D. and Beljonne, “Transiently delocalized states enhance hole mobility in organic molecular semiconductors,” Nat. Mater., vol. 22, pp. 1361-1369, 2023.

Giannini, L. Di Virgilio, M. Bardini, J. Hausch, J. Geuchies, W. Zheng, M. Volpi, J. Elsner, K. Broch, Y. H.

[3] S. Giannini, W. -T. Peng, L. Cupellini, D. Padula, A. Carof, and J. Blumberger, “Exciton transport in molecular organic semiconductors boosted by transient quantum delocalization,” Nat. Commun., vol. 13, p. 2755, 2022.

[4] J. Elsner, Y. Xu, E. D. Goldberg, F. Ivanovic, A. Dines, S. Giannini, H. Sirringhaus, and J. Blumberger, “Thermoelectric transport in molecular crystals driven by gradients of thermal electronic disorder,” Sci. Adv., vol. 10, p. eadr1758, 2024.

[5] K. Joll, P. Schienbein, K. M. Rosso, and J. Blumberger, “Machine learning the electric field response of condensed phase systems using perturbed neural network potentials,” Nat. Commun., vol. 15, p. 8192, 2024.

[6] K. Joll, P. Schienbein, K. M. Rosso, and J. Blumberger, in preparation, 2025.

This talk is part of the Theory - Chemistry Research Interest Group series.

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