Twenty years of physics: Atoms, molecules and electrons

CAN WE EVEN REMEMBER atomic, molecular and electron physics 20 years ago? When fine‐structure states of atomic hydrogen were still happily degenerate according to Dirac theory, and there was no conclusive demonstration to the contrary? When the dissociation energies of the simplest molecules such as nitrogen and carbon monoxide were unknown? When you could call an electron beam with 1‐eV energy spread a “monoenergetic beam” and leave the audience smiling approvingly?