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THESAURUS OF ULTRAVIOLET (UV)SPECTROSCOPY

Compound Identification Assignment

Nila Huda (1408100045) Kelas A

Ultraviolet (UV) spectroscopy

is one of the most common spectroscopic techniques by UV light absorption that cause

an electronic transition.

Ultraviolet (UV ) Light

is electromagnetic radiation with a wavelength shorter than that of visible light, but

longer than X-rays, in the range 10 nm to 400 nm, and energies from 3 eV to 124 eV

Absorption Spectrum

is the pattern of absorption (a plot of ultraviolet absorption intensity as function of

wavelenght).

Absorption Intensities

are rarely described quantitatively energy that was absorpted at the wavelenght.

Absorption Band

is a peak in UV spectrum represents absorption of energy.

Selection Rule

is a quantum mechanical rule that describes the types of quantum mechanical transitions

that are permitted.

Forbidden Transition

is one important selection rule states that transitions that involve a change in the spin

quantum number of an electronic during the transition are not allowed to take place.

HOMO (Higest Occupied Molecular Orbital)

is the highest molecular orbital that is uccupied by electron.

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LUMO (Lowest Unoccupied Molecular Orbital)

is the lowest molecular orbital that is not uccupied by electron.

Lambert-Beer Law

is the linear relationship between absorbance and concentration of an absorber of

electromagnetic radiation.

Molar Absorptivity

is a measurement of how strongly a chemical species absorbs light at a given

wavelength. It is an intrinsic property of the species.

Monochromator (diffraction grating)

is an optical device that separates and transmits a mechanically selectable narrow band

of wavelengths of light or other radiation chosen from a wider range of wavelengths

available at the input.

Detector

is generally a photomultiplier tube that recovers information of interest contained in a

modulated wave.

Chromophore

is a functional group capable of having characteristic electronic transitions.

Auxochrome

is a substituent which does not itself act as a chromophore but whose presence bring

about a shift of the absorbtion band toward the longer wavelength.

Bathochromic Shift (red shift)

is a band absorption shift to longer wavelength or lower energy due to increasing

stability as result of the presence of an auxochrome or also by decreasing polarity of

solvent.

Hypsochromic Shift (blue shift)

is a band absorption shift to shorter wavelength or higher energy due to decreasing

stability as result of the removal of conjugation and also by increasing the polarity of the

solvent .

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Hyperchromic Effect

is the effect that can increase intensity of absorption band because of increasing

concentration of the sample measured.

Hypochromic Effect

is the effect that can decrease intensity of absorption band because of decreasing

concentration of the sample measured.

Hyperconjugation

is the interaction result from overlap of the C- H bonding orbital with the system.

Woodward-Fieser Rules

are several sets of empirically derived rules which attempt to predict the wavelength of

the absorption maximum ( max) in an ultraviolet spectrum of a given compound.

Homoannular Diene

is a cyclic diene where the central bond is a part of the ring system and has cisoid ( s-cis )

orientation both double bonds are in the same ring.

Heteroannular Diene

is a cyclic diene where the central bond is a part of the ring system and has transoid ( s-

trans ) orientation both double bonds are not in the same ring.

Exocyclic Double Bond

is a double bond that lies outside of a given ring.