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.

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.

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.

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

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


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