2.1 The Nature of Radiant Energy The Duality of light: ● Refraction ● Reflection ● Diffraction ● Scattering (21) V frequency, c velocity of light, n wavelength, v wave number
2.1 The Nature of Radiant Energy The Duality of Light: 1. Wave properties ⚫ Refraction ⚫ Diffraction cv c v = = ⚫Reflection ⚫Scattering V frequency, C velocity of light , wavelength, v wave number __ (2.1) -
2. Particular proper( the Energy of a photor hc e=hv= =hCw(22) Where h is planck's constant =6.6256×10-34J.s
hcv hc E = hv = = Where h is Planck’s constant, h=6.6256×10-34 J.s 2. Particular proper ( the Energy of a photon) (2.2)
2.2 Spectral Regions The most important spectral regions: spectral regions transitions X ray K- and L-shell electrons Far ultraviolet Middle-shell electrons Near ultraviolet Valence electrons Visible Valence electrons Near and mid infrared Molecular vibrations Far infrared Molecular rotations
2.2 Spectral Regions The most important spectral regions: spectral regions transitions X ray K- and L-shell electrons Far ultraviolet Middle-shell electrons Near ultraviolet Valence electrons Visible Valence electrons Near and mid infrared Molecular vibrations Far infrared Molecular rotations
2.3 Interaction of Radiation with Atoms Emission Atom(high excited state)->Atom(lower excited state)+ hv Absorption Atom(ground state)+ hv-> Atom(high excited state) Fluorescence Atom(ground state)+ hv-> Atom(high excited state) ->Atom (lower excited state)+ hvE
2.3a Interaction of Radiation with Atoms ▪ Emission Atom (high excited state) → Atom (lower excited state) + h ▪ Absorption Atom (ground state) + h → Atom (high excited state) ▪ Fluorescence Atom (ground state) + h → Atom (high excited state) → Atom (lower excited state) + hF
+Energy Excitation Deci Figure 1-1. Bohr model of an atom As energy is absorbed by an atom, an elec tron jumps to an orbital with a higher energy level. The atom may decay to a ower energy state by emitting a photon, hy