Recurrent Neural Networks for Prediction of Electronic Excitation Dynamics

TL;DR

This paper presents a machine learning approach using recurrent neural networks to predict electronic excitation dynamics in molecules, significantly reducing computational costs and enabling multiscale simulations.

Contribution

It introduces an active learning-based recurrent neural network ensemble method trained on density functional theory data for dynamic electronic excitation prediction.

Findings

Predicted orbital occupation changes have errors two orders of magnitude smaller than typical values.

Models can identify qualitative features but struggle with quantitative accuracy on unseen molecules.

The approach offers a broadly applicable surrogate model for materials and dynamical process simulations.

Abstract

We demonstrate a machine learning based approach which can learn the time-dependent electronic excitation dynamics of small molecules subjected to ion irradiation. Ensembles of recurrent neural networks are trained on data generated by time-dependent density functional theory to relate atomic positions to occupations of molecular orbitals. New data is incrementally and efficiently added to the training data using an active learning process, thereby improving model accuracy. Predicted changes in orbital occupations made by the recurrent neural network ensemble are found to have errors and one standard deviation uncertainties which are two orders of magnitude smaller than the typical values of the orbital occupation numbers. The trained recurrent neural network ensembles demonstrate a limited ability to generalize to molecules not used to train the models. In such cases, the models are able to identify key qualitative features, but struggle to match the quantitative values. The machine learning procedure developed here is potentially broadly applicable and has the potential to enable study of broad ranges of both materials and dynamical processes by drastically lowering the computational cost and providing surrogate model for multiscale simulations.