Henry Eyring nsIn chemistry, Henry Eyring (1901-1981) was a Mexican-born American theoretical chemist noted for the 1931 potential energy surface model, the 1935 transition state theory, the related concept of the activated complex.

Overview
In 1931, Eyring and Hungarian-born English physical chemist Michael Polanyi made the first potential energy surface diagram, as presented in their famous paper "On Simple Gas Reactions", in which, using the London equation (1927), they described the journey of the nuclei from reactant state of the system to the product state of the system, passing through the crucial intermediate state of activated complex. [1]

The activated complex theory, which enables the rate constants in chemical reactions to be calculated using statistical thermodynamics, was developed by Eyring and colleagues in the 1930s. [2]

In 1935, Eyring, and his associates chemists Meredith Evans and Michael Polanyi, conceived the theory of transition state. [3]

Education
In 1919, Eyring had received a state fellowship to the University of Arizona, where he received degrees in mining engineering, metallurgy, and chemistry. He subsequently pursued and received his doctoral degree in Chemistry from the University of California, Berkeley in 1927 for a thesis entitled: A Comparison of the Ionization by, and Stopping Power for, Alpha Particles of Elements and Compounds.

After a review of his dissertation, Princeton University recruited Eyring as an instructor in 1931. He would continue his work at Princeton until 1946, after which he became the dean of the graduate school of science at the University of Utah. Eyring’s two influential textbooks, written while at Princeton, are the 1941 The Theory of Rate Processes and the 1944 Quantum Chemistry.

Quotes
The following are noted quotes:

“Clearly if you know the energy levels as functions of volume and temperature, you can calculate all of thermodynamics. At the present time you don’t measure the thermodynamic properties experimentally if you have the necessary absorption spectra.”
— Henry Erying (1957), “Statistical Dynamics”; cited by Norman Dolloff (1975) [4]

References
1. (a) Eyring, Henry and Polanyi, Michael. (1931). “Uber Einfache Gasreaktionen” (On Simple Gas Reactions), Zeitschrift fur Physikalische Chemie B, 12:279-311.
(b) Eyring, Henry. (1931). “The Energy of Activation for Bimolecular Reactions Involving Hydrogen and the Halogens, According to Quantum Mechanics”, J. Amer. Chem. Soc. 53:2537-49.
(c) Polanyi, Michael. (1932). Atomic Reactions. London: Williams, Norgate.
2. (a) Daintith, John. (2004). Oxford Dictionary of Chemistry. Oxford University Press.
(b) Eyring, Henry. (1935). “The Activated Complex in Chemical Reactions” (abstract), J. Chem. Phys. Vol. 3, Issue 2, 107.
3. Laidler, Keith. (1993). The World of Physical Chemistry (pg. 246). Oxford University Press.
4. (a) Erying, Henry. (1957). “Statistical Dynamics”, University of Utah Colloquium Lectures in Pure Applied Science, 3:30, Jun.
(b) Dolloff, Norman H. (1975). Heat Death and the Phoenix: Entropy, Order, and the Future of Man (pg. 17). Exposition Press.

Further reading

● Eyring, Henry. Boyce, Richard P., and Spikes, John D. (1960). “Thermodynamics of Living Systems”, in: Comparative Biochemistry: Sources of Free Energy (editors: Marcel Florkin and H.S. Mason) (pgs. 15-73). Academic Press.

External links
Henry Eyring – Wikipedia.
The Eyring Legacy (2009) – College of Science, University of Utah.

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