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Spectroscopy is the study of the interaction of electromagnetic radiation, such as ultra-violet and visible light, with matter.  Ultra-violet and visible light  spectroscopy is the measurement of the wavelength and intensity of transmittance or absorption of ultraviolet and visible light of a sample. Ultraviolet and visible light are energetic enough to promote outer electrons to higher energy levels.  UV-vis spectroscopy is usually applied to molecules and inorganic ions or complexes in solution. The uv-vis spectra have broad features that are of limited use for sample identification but are very useful for quantitative measurements. The concentration of a sample in solution can be determined by measuring the transmittance at some wavelength and applying the Beer-Lambert Law.  Transmittance is the preferred physical measurement as it is linear on the spectrophotometers meter scale and absorbance is logarithmic and harder to read accurately. 

A = 2 - log(%T)


%T = the percent of transmittance of light through a sample.

A = absorbance

A = ecl

Absorbance is directly related to concentration if measurements are made at a fixed wavelength in a cell of constant path length and the sample obeys the Beer-Lambert Law.  

Light spectrum of colors visible by unaided human eye.

    visible visible visable visible visible visible visible  
  Ultra  Violet Violet Indigo Blue Green Yellow Orange Red Infra Red
(l Range) 190-400 400-460  460-475  475-490  490-565  565-575  575-600  600-800  900-1400
(Avg. l) 295 430 467.5 482.5 527.5 570 587.5 700 1150
(Energy) 10-3 4.65 4.25 4.15 3.8 3.475 3.375 2.9 (10-19 J)

A database of spectral lines can be found at this URL:
NIST Scientific and Technical Databases - Online Scientific

Mass Spectroscopy

A History of Mass Spectroscopy
FTIR TroubleshootingThe FTNMR Free Induction Decay Archive
Instrumentation and Ionization Methods Tutorial
Mass Spectroscopy Tools
Nuclear Magnetic Resonance (NMR)
Organic Structure Elucidation A Workbook of Unknowns
SDBS - Integrated Spectral Data Base System for Organic Compounds
Secondary Ion Mass Spectrometry
Secondary Ion Mass Spectrometry (SIMS) Home Page
Spectroscopic Tools  


Use of the Spectonic 20 at a fixed wavelength
Use of the Spectronic
Detecting blood Glucose with the Spec 20

Spectronic 20 Spectrophotometer
Spectronic 20 (calibration)
Spectronic 20-D Operation
Spectronic 20

Overview of Spectronic 10 Controls
Chemlab - Spectronic Instructions - GREAT!

Other Web Links


Spectroscopy - Home Page
spectroscopyNOW.com - spectroscopy and spectrometry portalwww.sciencedirect.com/science/journal/09242031
Optics and Spectroscopy
USGS Spectroscopy Lab - home page
Year 2: NMR Spectroscopy
WebSpectra - Problems in NMR and IR Spectroscopy
Society for Applied Spectroscopy Home Page
Thermal Emission Spectrometer Project Homepage
The Science of Spectroscopy (www.scienceofspectroscopy.info)

IR Spectroscopy Tutorial
JPL Molecular Spectroscopy
Spectroscopy Europe: a wealth of information on spectroscopy
Spektroskopische Tools/Spectroscopic Tools :: Steffen's Science
Mineral Spectroscopy
SAS 2002 Election Results
Spectroscopy - Wikipedia, the free encyclopedia
Chemistry > Spectroscopy in the Yahoo! Directory


WinTorg is a Windows simulation program that shows university
and college students how to use spectroscopy to identify organic
compounds. There are 100 unknowns available.
Spectroscopy is emphasized (pmr, cmr, ir, ms, uv) and the
unknowns can be identified by spectroscopy and/or chemical tests
and/or derivatives. Extensive context-sensitive help is available
and the program can be highly customised.
For more information and to download a free shareware version
with 3 unknowns go to:


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