Bridging the Gap Between Theory and Experiment with Machine Learning Open Access
Chen, Xu (Spring 2026)
Abstract
Accurately linking theoretical predictions with experimental measurements remains a central challenge in computational chemistry. Quantum mechanics provides a rigorous foundation for describing molecular systems, yet its direct application to realistic chemical environments is often computationally prohibitive. Machine learning has emerged as a powerful complement, capable of improving efficiency and predictive performance; however, many models sacrifice interpretability and robustness, particularly in noisy or data-scarce experimental settings. Overcoming these limitations requires approaches that enhance predictive accuracy, interpretability, transferability, and accessibility. In this dissertation, I address these challenges from several complementary perspectives. First, Δ-machine learning is employed to correct systematic biases in implicit-solvent (time-dependent) density functional theory calculations, thereby reducing functional dependence and improving agreement with experimental redox potentials and absorption energies. Second, to overcome the scarcity of experimental data, I develop a domain-adversarial framework that combines abundant simulated spectra with limited experimental measurements to detect thermodynamic phase transitions from angle-resolved photoemission spectroscopy. Applied to cuprate superconductors, this framework achieves over 97% accuracy in identifying phase transitions from experimental spectra. Third, I develop ACES-GNN, a graph neural network trained with activity-cliff explanation supervision that simultaneously improves predictive performance and interpretability. Finally, I develop AutoSolvate-Agent, a large-language-model-driven autonomous system that automates simulation setup, error recovery, and interactive interpretation for advanced solution-phase quantum chemistry.
Table of Contents
Chapter 1. Introduction ................................................. 1
1.1 Computational methods for molecular property prediction .......... 2
1.2 Representation of molecular and material system ................. 11
1.3 Interpretability of machine learning models ..................... 19
1.4 Outline of the dissertation ..................................... 24
Chapter 2. Δ-Machine learning for quantum chemistry prediction of
solution-phase molecular properties at the ground and excited states ... 28
2.1 Introduction .................................................... 29
2.2 Methods ......................................................... 31
2.3 Results and discussion .......................................... 39
2.4 Conclusions ..................................................... 54
2.5 Acknowledgments ................................................. 55
Chapter 3. Detecting thermodynamic phase transition via explainable
machine learning of photoemission spectroscopy ......................... 57
3.1 Introduction .................................................... 58
3.2 Methods ......................................................... 61
3.3 Results and discussion .......................................... 67
3.4 Conclusions ..................................................... 79
3.5 Acknowledgments ................................................. 81
3.6 Appendix ........................................................ 81
Chapter 4. ACES-GNN: Can graph neural network learn to explain activity
cliffs? ............................................................... 90
4.1 Introduction .................................................... 91
4.2 Methods ......................................................... 95
4.3 Results and discussion ......................................... 102
4.4 Conclusions .................................................... 115
4.5 Acknowledgments ................................................ 116
Chapter 5. AutoSolvate-Agent: an autonomous agent for GPU-accelerated
solution-phase quantum chemistry ...................................... 118
5.1 Introduction ................................................... 118
5.2 Methods ........................................................ 122
5.3 Results and discussion ......................................... 125
5.4 Conclusions .................................................... 130
5.5 Acknowledgments ................................................ 130
Chapter 6. Conclusions and perspectives ............................... 131
Bibliography .......................................................... 137
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