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A UV-Vis spectrophotometer is an analytical instrument that measures the amount of ultraviolet (UV) and visible light that is absorbed by a sample. It is a widely used technique in chemistry, biochemistry, and other fields, to identify and quantify compounds in a variety of samples.
UV-Vis absorption SEC is a recent technique that is continuously evolving. However, many advantages have been observed over other techniques. However, many advantages have been observed over other techniques.
Ultraviolet-visible (UV-vis) spectroscopy involves energy levels that excite electronic transitions. Absorption of UV-vis light excites molecules that are in ground-states to their excited-states. [5] Visible region 400–700 nm spectrophotometry is used extensively in colorimetry science. It is a known fact that it operates best at the range ...
Ultraviolet–visible spectroscopy (UV–vis) can distinguish between enantiomers by showing a distinct Cotton effect for each isomer. UV–vis spectroscopy sees only chromophores , so other molecules must be prepared for analysis by chemical addition of a chromophore such as anthracene .
If Albert Einstein's photoelectric law is applied to a free molecule, the kinetic energy of an emitted photoelectron is given by =, where h is the Planck constant, ν is the frequency of the ionizing light, and I is an ionization energy for the formation of a singly charged ion in either the ground state or an excited state.
In modern spectrographs in the UV, visible, and near-IR spectral ranges, the spectrum is generally given in the form of photon number per unit wavelength (nm or μm), wavenumber (μm −1, cm −1), frequency (THz), or energy (eV), with the units indicated by the abscissa.
The restriction of the spin selection rule makes it even easier to predict the possible transitions and their relative intensity. Although they are qualitative, Tanabe–Sugano diagrams are very useful tools for analyzing UV-vis spectra: they are used to assign bands and calculate Dq values for ligand field splitting. [13] [14]
Photochemical immersion well reactor (50 mL) with a mercury-vapor lamp.. Photochemistry is the branch of chemistry concerned with the chemical effects of light. Generally, this term is used to describe a chemical reaction caused by absorption of ultraviolet (wavelength from 100 to 400 nm), visible (400–750 nm), or infrared radiation (750–2500 nm).