First, we have partitioned the QM9 datasets on the train, validation and test subsets (QM9 TR , QM9 VAL , and QM9 TEST , respectively), so that the validation part contains 2500 molecules, and the test part contains 5000 molecules. For the consistency reasons, VAE was trained on the combined ZINC + QM9 TR dataset, and QM9 VAL was used for validation; for the training procedure of regression, QM9 TR and QM9 VAL were used; QM9 TEST was used as test data across HOMO prediction and reconstruction of molecules.