After using 85% of the training set to train the model for testing purposes, the final random forest model was trained using the full data set for screening a larger validation set to predict the λ of 24,853 tetramers and 31,722 hexamers that were not part of the original data set. From those new predicted λ, oligomers with λ < 0.3 eV were filtered to compute the full B3LYP λ, including 660 tetramers and 1753 hexamers with low λ (Figure a, b). The increase in the number of oligomers with λ < 0.3ev from the tetramers to the hexamers agrees with assessment of the inverse relationship between the length of the oligomer and its reorganization energy .