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THESAURUS OF INFRARED (IR)

Compound Identification Assignment

Nila Huda (1408100045) Kelas A

Infrared (IR) Spectroscopy

is one of the most common spectroscopic techniques used by organic and inorganic

chemists for identification of functional group.

Infrared Spectrum

is the pattern of absorption (a plot of % infrared absorption intensity/transmittance as

function of wavenumber).

Infrared Absorption Intensities

are rarely described quantitatively, except for the general classifications of s (strong), m

(medium) or w (weak).

Monochromator

is a device used to disperse a broad spectrum of radiation and provide a continuous

calibrated series of electromagnetic energy bands of determinable wavelength or

frequency range.

Prisms or Gratings

are the dispersive components used in conjunction with variable-slit mechanisms,

mirrors, and filters. For example, a grating rotates to focus a narrow band of frequencies

on a mechanical slit.

Detector

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

modulated wave.

Fourier Transform Infrared (FTIR)

is the type instrument that can separate the individual absorption frequencies from

interferogram, producing a spectrum virtually identical to that obtained with dispersive

spectrometer.

Interferogram

is the design of the optical pathway produces a pattern, essentially a plot of intensity

versus time.

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Hooke Law

is approximation that states that the extension of a spring is in direct proportion with the load

applied to it

Moment Dipole

can be defined as the product of magnitude of charge & distance of separation between thecharges

Wavenumber

is another way to describe the frequency of electromagnetic radiation, and the one most

often used in infrared spectroscopy.

Wavelengths ()

is Inversely proportional to frequencies and their associated energy

Transmittance (T)

is the ratio of radiant power transmitted by the sample (I) to the radiant power incidenton the sample (I0).

Absorbance (A)

is the logarithm to the base 10 of the reciprocal of the transmittance (T).

StretchingVibration

is a vibration occurring along the line of the bond that changes the bond length.

BendingVibration

is a vibration that does notoccur along the line of the bond, but changes the bond angle.

Functional Group Region

is the left-hand two-thirds of an IR spectrum (from 4000 to 1300 cm1) usually comes from

stretching vibrations between hydrogen and some other atoms.

Fingerprint Region

is The right-hand third of the IR (from about 1300 to 500 cm-1) usually contains a very

complicated series of absorptions. These are mainly due to all manner of bending vibrations

within the molecule.

Fundamental Absorption

is downward spike in the IR spectrum represents absorption of energy at normal

frequencies.

Overtone

is any frequency higher than the fundamental frequency of a sound resulted from

excitation.

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Combination Band

is the band observed when more than two or more fundamental vibrations are excited

simultaneously the sum of two interacting band fundamental and overtone,

Vcomb = V1 + V2

Difference Band

is the band observed from difference between two interacting band fundamental and

overtone, Vdiff= V1 - V2

Fermi Resonance

is the coupled vibration it results in the splitting of two vibrational bands that have

nearly the same energy and symmetry. The two bands are usually a fundamental

vibration and either an overtone or combination band.