The<unk>  attempts to describe the relationship between the physical magnitudes of stimuli and the perceived intensity of the stimuli. Ernst Heinrich<unk>  (1795–1878) was one of the first people to approach the study of the human response to a physical stimulus in a quantitative fashion. Gustav Theodor<unk>  (1801–1887) later offered an elaborate theoretical interpretation of<unk> 's findings, which he called simply<unk> 's<unk> , though his admirers made the<unk> 's name a hyphenate.
Weber–Fechner law
Franck-Condon principle
SN2 reaction
Van der Waals strain
Disulfide bond
Aldol reaction
Degenerate energy level
Behrens-Fisher problem