In the 2023 film Oppenheimer based on the 2005 biography American Prometheus by Kai Bird and Martin J. Sherwin, there seems to be two references to work by Oppenheimer on molecules:
RABI: I caught your lecture on molecules. Caught some of it.
and
HEISENBERG: I liked your paper on molecules.
I'm guessing this reference is related in some way to what we now call the Born–Oppenheimer approximation since (earlier?) Bohr had sent him to Göttingen to study with Born.
Question: What paper or papers about molecules did Heisenberg "like", and what has Heisenberg published or otherwise commented about it in a well-documented way?