Linus Pauling: In 1929, Fritz London developed his quantum mechanical theory of Van der Waals attraction.
Which is that as the electrons move around the nucleus, in say the xenon atom, they
are not equally distributed on the right and left side of the nucleus so that the
center of charge of the electrons coincides with the nucleus that carries the positive
charge, but there are fluctuations in the position of the center of charge so that
there is an instantaneous electric dipole moment, producing them instantaneously in
an electric field. And that for a second xenon atom, too, there is an instantaneous
electric dipole moment. And these two instantaneous dipole moments interact with one
another in a way that, in accordance with the fundamental principle of quantum mechanics,
leads to attraction.
This was very good, very interesting, it interested me very much in 1929 because this
phenomenon of condensation, formation of a liquid and then of a crystal, comes close
to chemistry. At any rate, it's an important part of the world and I've tried to understand
the physical world all of my life.