Walter Kohn (born March 9, 1923) is an Austrian-born American theoretical physicist.He was awarded, with John Pople, the Nobel Prize in chemistry in 1998. The award recognized their contributions to the understandings of the electronic properties of materials. In particular, Kohn played the leading role in the development of density functional theory, which made it possible to incorporate quantum mechanical effects in the electronic density (rather than through its many-body wavefunction).