The actual atoms and molecules that make up my brain and body today are not the same ones that I was born with on September 8, 1954, a half-century ago this month. ↗
It does not seem, however, that organic chemists were much worried about barriers to rotation in organic molecules in general at that time because there was no technique available to demonstrate the phenomenon experimentally. ↗
I must confess that, at that time, I had absolutely no knowledge of the slowness of the relaxation processes in the ground state, processes which take place in collisions with the wall or with the molecules of a foreign gas. ↗