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"The Future of Physical Chemistry"
 
"The Future of Physical Chemistry" May 7, 1968.
Symposium in Dedication of the Arthur Amos Noyes Laboratory of Chemical Physics, California Institute of Technology, Pasadena.

A.A. Noyes and Richard Tolman. (3:57)

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Linus Pauling: Here we had A.A. Noyes who was determined that the new physics, the new discoveries in physics that were being made, would be included, incorporated within the body of physical chemistry. And Tolman, who Noyes had selected, and who was really an extraordinary man -- Tolman worked on the theory of relativity in these early days. Tolman was himself more active in this respect than Noyes who, whose training had been of the old-fashioned sort. Mathematics was something of a strain for him except the simple mathematics of thermodynamics.

And ah...but this wasn't true of Tolman. One of the early experiments that Tolman carried out was to centrifuge a solution of cesium fluoride. His contention was that if our ideas about electrolytes were right, and about nature as a whole, the cesium ion ought to go out to the ends, they ought to fall in the pseudo-gravitational field and the fluoride ions would not be forced out so strongly. And there should be produced a potential difference from centrifugation. And he carried out this experiment. And then he got to thinking about the mass of the electric conductor in metals and out on the camps, about where, well, up against, about where the biology lab is now he had a little building in which he jiggled a cylinder of metal and by making some sort of electromagnetic operations on it was able to calculate what the, what it was that carried the electric charge. If you move a piece of metal and then stop it suddenly the electrons keep moving, a little current appears, which he measured. He was interested in the heat capacity of hydrogen gas.

He and Professor Badger, Badger wasn't a professor then of course, and they tried very hard to understand, to develop a quantum theory of the heat capacity of hydrogen. They were unsuccessful in doing this. It wasn't until 1927 that David Dennison, the father of the young Dennison who took his PhD degree here recently, uh, 1927 that David Dennison realized that protons have a spin and that the molecules H2 in which the proton spins are parallel and those in which they are antiparallel are meta-stable transitions between the parallel and the antiparallel rotati...orientations of proton spins are slow. And that what one was measuring, in measuring the heat capacity of hydrogen gas, was not an equilibrium heat capacity but rather the heat capacity of a frozen in non-equilibrium mixture at temperatures below room temperature with 25% of the antiparallel spin, 75% of the parallel spin forms of hydrogen.

Clip

Creator: Linus Pauling
Associated: A. A. Noyes, Richard Tolman, Richard Badger, David Dennison
Clip ID: 1968v.4-noyes

Full Work

Creator: Linus Pauling, Norman R. Davidson
Associated: California Institute of Technology

Date: May 7, 1968
Genre: sound
ID: 1968v.4
Copyright: More Information


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