Ultraviolet–Visible Spectroscopy
A technique that measures the absorption of ultraviolet and visible light by electronic transitions within molecules.
Formula / equation
A = log(I₀/I)
Unit
nm
In depth
Absorption promotes electrons between molecular orbitals, typically pi to pi star or n to pi star. The wavelength of maximum absorption indicates the extent of conjugation, while the absorbance gives concentration through the Beer–Lambert law.
Examples in the real world
Quantifying DNA at 260 nm; following an enzyme reaction by the appearance of a coloured product.