Machine learning exciton dynamics† †Electronic supplementary information (ESI) available. See DOI: 10.1039/c5sc04786b

• Published in: Chemical science (Cambridge) Vol. 7; no. 8; pp. 5139 - 5147
• Main Authors: Häse, Florian, Valleau, Stéphanie, Pyzer-Knapp, Edward, Aspuru-Guzik, Alán
• Format: Journal Article
• Language: English
• Published: Royal Society of Chemistry 01.04.2016
• Subjects: Chemistry
• ISSN: 2041-6520; 2041-6539
• DOI: 10.1039/c5sc04786b

Machine learning ground state QM/MM for accelerated computation of exciton dynamics. Obtaining the exciton dynamics of large photosynthetic complexes by using mixed quantum mechanics/molecular mechanics (QM/MM) is computationally demanding. We propose a machine learning technique, multi-layer perceptrons, as a tool to reduce the time required to compute excited state energies. With this approach we predict time-dependent density functional theory (TDDFT) excited state energies of bacteriochlorophylls in the Fenna–Matthews–Olson (FMO) complex. Additionally we compute spectral densities and exciton populations from the predictions. Different methods to determine multi-layer perceptron training sets are introduced, leading to several initial data selections. In addition, we compute spectral densities and exciton populations. Once multi-layer perceptrons are trained, predicting excited state energies was found to be significantly faster than the corresponding QM/MM calculations. We showed that multi-layer perceptrons can successfully reproduce the energies of QM/MM calculations to a high degree of accuracy with prediction errors contained within 0.01 eV (0.5%). Spectral densities and exciton dynamics are also in agreement with the TDDFT results. The acceleration and accurate prediction of dynamics strongly encourage the combination of machine learning techniques with ab initio methods.