ENCH 213 Lecture Notes - Monochromator, Molar Attenuation Coefficient, Ais People

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Spectro = spectrum photo = photon: metry = measurement = display of radiation intensity (emitted, absorbed or scattered) vs photon energy light = electromagnetic radiation = perpendicular oscillating electric and magnetic fields. Properties of light: wavenumber = # waves/cm = 1/ = v. = wavelength frequency, v: # oscillations/s, 1 oscillation/s = 1 hz, determined by the radiation source, constant regardless of medium traversed. Relation between frequency and wavelength vi = velocity of propagation: dependent on both frequency and the medium traversed. Iv = vi in vacuum (or air at 3 sig. fig. ), vi = c = speed of light = 3. 00x1010 cm/s if not in vacuum, vi = c/n: where n=refractive index (>1) as v= constant for a given light source. Since light interacts with matter, it can be treated as packets of energy called photons a photon carries energy, e = hv: h= planck"s constant = 6. 63x10-34 j s, e = hc/ = hcv, longer involves less energy.