The award of the Nobel prize for chemistry to Walter Kohn of the University of California at Santa Barbara and John Pople of Northwestern University, Illinois, signals a recognition that computational chemistry is now a tool at the chemist's disposal to equal any experimental or analytical technique.
Kohn provided the theoretical framework for calculating the electronic structure of molecules without having to grapple with the formidable task of solving the full Schrödinger equation. He showed that the total energy of a system can be expressed simply in terms of the distribution of its electron density, without regard to the details of the electron motions; the density is a function of the spatial coordinates, and the energy is a ‘function of a function’, or a functional.
Kohn developed what was later to be called density functional theory in 1964, with applications in physics in mind. This theory is now widely used to calculate the electronic band structures of solids, and also in liquid-state physics.
The application of approximate computational methods to chemistry, meanwhile, was pioneered by Pople. Towards the end of the 1960s he developed the GAUSSIAN-70 program for calculating the electronic structure of molecules and the nature of their interactions and reactions.
Current modifications of this program are now used by thousands of chemists throughout the world, according to Roberto Car of the Ecole Polytechnique Fédérale in Lausanne, Switzerland. “[Pople] has built an industry around this,” says Car.
That view is echoed by Nicholas Handy at the University of Cambridge, who feels that the laureates are “exactly the right two people” to be recognized.
About this article
International Studies in the Philosophy of Science (2000)