Analytical Chemistry Trinidad & 

Tobago Lab Resources

Application of EM Spectrum in Analytical spectroscopy

Spectroscopy use the energy of Electromagnetic Radiation to study matter. Analytical techniques include computer and fiber optics to extend the use of "chemometrics" procedures to build new spectrometers and spectrophotometers with applications in the field of chemistry and the sciences. Manufacturers harness the interactions of Electromagnetic radiation to separate waves of different frequencies so that the radiation can be measured as a function of frequency or wavelength.

Instrument Parameters and Spectral range


Spectral region/
Technique
Radiation source Monochromator Detector
Vacuum UV Argon dye laser Fluorite Prism Photomultiplier
UV Xenon lamp
Hydrogen lamp
Deuterium lamp
Fused silica
Quartz Prism
Phototube
Photo diode array (PDA)
Photomultiplier Tube (PMT)
UV - VIS Xenon lamp Fused silica/Quartz Prism Phototube, PDA, PMT
VIS Tungsten lamp Glass Prism
Interference Filters
Phototube, PMT
Silicon diode
IR Nerst Glower
(ZrO2 and Y2O3)
Nichrome wire
NaCl Prism
Grating 10 / 200 lises/mm
Interference filters
Photoconductor
Pyroelectric cell (capacitance)
Thermocouple (volts)
Bolometer (ohms)
Far IR Globar (SiC) KBr Prism (TlBr) Golay pneumatic cell

Spectral range and electron transitions


Radiation
Type
Radiation Source Frequency Range (Hz) Wavelength Range Type of Transitions
gamma rays    1020 - 1024 <10-12 m nuclear
X-rays   1017 - 1020 0.01nm - 10nm (1 pico meter) inner electron
ultraviolet deuterium lamp 1015 - 1017 400 nm - 1 nm outer electron. Electronic transitions, vibrational fine structure
visible Tungsten lamp 4 - 7.5 x 1014 750 nm - 400 nm
near-infrared Tungsten, dye laser 1 x 1014 - 4 x 1014 2500 nm - 750 nm (2.5 um - 750 nm) outer electron molecular vibrations. Vibrational transitions, rotational fine structure
infrared nerst glower, globar, Xe,Ar, discharge lamp 1013 - 1014 250,000 - 2,500 nm (25um - 2.5 um) outer electron, molecular vibrations. Vibrational transitions, rotational fine structure
microwaves   3 x 1011 - 1013 250,000 - 1,000,000,000 nm (1 mm - 25 um) molecular rotations,electron spin flips*, Rotational transitions
radio waves   <3 x 1011 >1 mm nuclear spin flips*
* energy levels split by a magnetic field.


Applications with Electromagnetic Radiation
Consisting of all frequencies from low frequency Radio waves to high energy Gamma rays.
These waves cover technology from communications to Space Exploration.
There is no division between different types of waves. it is a continuous spectrum that blends seamlessly into one another. The wavelenghts and frequencies are inversely related to each other.
Electromagnetic waves-like and particle-like properties known as wave particle duality.


The Colors of Visible Radiation ¹



Wavelength Range nm Color seen by Instrument
Absorption color
Color seen by Human Eye
Complement color
400 - 465 Violet Yellowish green
465 - 482 Blue Yellow
482 - 487 Greenish blue Orange
487 - 493 Blue green Red orange
493 - 498 Bluish green Red
498 - 530 Green Red purple
530 - 559 Yellowish green Reddish purple
559 - 571 Yellow green Purple
571 - 576 Greenish yellow Violet
576 - 580 Yellow Blue
580 - 587 Yellowish orange Blue
587 - 597 Orange Greenish blue
597 - 617 Reddish orange Blue green
617 - 780 Red Blue green

Applications with Electromagnetic Radiation
Consisting of all frequencies from low frequency Radio waves to high energy Gamma rays.
These waves cover technology from communications to Space Exploration.
There is no division between different types of waves. it is a continuous spectrum that blends seamlessly into one another. The wavelenghts and frequencies are inversely related to each other.
Electromagnetic waves-like and particle-like properties known as wave particle duality.


Reference:
1. "Analytical Absorption Spectroscopy", D.B. Judd; M.G. Melon (Ed.)
Chap. 9, Wiley, New York, 1950.


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,BR.
Signature: Dhanlal De Lloyd, Chem. Dept, The University of The West Indies, St. Augustine campus
The Republic of Trinidad and Tobago.
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