Chemistry was earlier a descriptive science. The fact that most of the studies in chemistry had not the rigor of mathematics was the reason that chemistry was developed by the great experimentalists.
However, in the beginning of quantum mechanics, a chemical physicist, Robert S. Mulliken, who was a brilliant spectroscopist started developing the orbital theory, atomic orbitals and then molecular orbitals to describe the bonding and calculating the energies from the spectra of molecules and won his Nobel Prize in chemistry.
Herzberg was a Canadian physical chemist, for twenty years, he was head of the physics division of National Research Council in Ottawa which he made into a world-renowned spectroscopie laboratory, studied free radicals and Lamb shift in hydrogen like atoms with highly ionized atoms. He got his Nobel Prize in Chemistry in 1971.
Coulson had made enormous contribution to molecular orbital theory. Being a mathematician, he built theoretical chemistry, more...