When it comes to predicting experimental values of molecular
properties
with deep learning, the key problem is the lack of sufficient experimental
data for training. We propose a method that consists of pretraining
a graph neural network that aims to reproduce first-principles quantum
mechanical results, followed by fine-tuning of a fully connected neural
network against experimental results. The combined pretraining and
fine-tuning model is expected to yield molecular properties close
to experimental accuracy. This is made possible because first-principles
quantum mechanical methods are often qualitatively correct or semiquantitatively
accurate; thus, a calibration of the calculation results against high-precision
but limited experiment data can improve accuracy greatly. Moreover,
the method is highly efficient, as first-principles quantum mechanical
calculation is bypassed. To demonstrate this, we apply the combined
model to determine the experimental heats of formation of organic
molecules made of H, C, O, N, or F atoms (up to 30 atoms), where mere
405 experimental data are used. The overall mean absolute error is
1.8 kcal/mol for these molecules.