2012 Product Catalogue

Specac Product Catalogue 2012 | A-Z of IR
A-Z of IR
Omni Cell
With over 400 window and pathlength
combinations available as standard, to cater for
every sample and wavelength of interest,
Specac’s Omni Cell is the simple stand most
versatile Infrared transmission cell system
available anywhere. The Omni Cell can be
configured as a sealed liquid cell, a demountable
liquid cell, or a mull cell. Easily assembled, or
disassembled, in a few seconds, it is designed
for fast sample turn-around. With a known
pathlength, the spectrum from an Omni Cell
is suitable for Quantitative Analysis.
P
Peak-to-Peak Noise
A noise measurement often made on a 100%
Line to determine spectrum quality and
instrument performance when obtained under
controlled conditions. It is measured as the
difference between the lowest and highest
transmittance value in a specific wavenumber
range.
Polarizer
A device for converting light into polarized light.
Typically, polarizers are a ZnSe substrate with
thin parallel gold wires on the surface to form
a grid.
Polymer film
A thin film, of precise thickness, pressed at an
elevated temperature using a Specac
Constant Thickness Film Maker Kit. The film can
then be mounted in a magnetic film holder before
being placed directly in the Infrared beam for
transmission analysis.
Q
Quantitative Analysis
Calculation of sample concentration using
measurements from a spectrum, such as band
ratios and peak areas and heights.This technique
requires a calibration before unknown
concentrations can be determined.
R
Raman effect
When monochromatic light is scattered by
molecules, a small fraction of the scattered light
is observed to have a different frequency from
that of the incident beam; this is the Raman
effect. Raman spectroscopy can reveal vibrations
that may be inactive under Infrared analysis, and
therefore can provide complementary
information about the molecular structure of the
sample under examination. The Specac Variable
Temperature Cell holder is suitable for the Raman
Technique.
Reflection Absorption
Also known as “Double-transmission”, reflection
absorption is a sampling technique used on thin
coatings on metal. The Infrared beam passes
through the coating again after reflecting off the
metal surface, before reaching the detector.
Refractive Index
See Index of Refraction.
Resolution
Measure of the ability of a spectrometer to
distinguish features of a spectrum which are very
close together.
S
Scan
The measuring of an interferogram in FTIR.
Usually involves cycling the mirror in the
interferometer once.
Sealed Liquid Cells
Basic accessories used to obtain transmission
spectra of liquids. Consists of two IR transparent
windows (e.g. NaCl), held apart by a spacer,
filled with the liquid under consideration. The cell
is then put directly into the beam. Specac’s
advanced Omni-Cell system can be configured
for use as a sealed liquid cell, with 9 options for
windows and 6 options for pathlength to give 54
standard combinations.
Cont’d
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