1. Lecture 11 Atomic absorption

2. Only photons of one specified wavelength are absorbed Ground state Excited state

3. Width Doppler Speed of light 300,000,000 m/s Velocity of a particle >1000 m/s collisions Approximately as Doppler Both effects increase with the temperature and decrease with the size of the molecule/atom Multiple energy levels Width is around 0.01-0.001 nm in visible area

4. Energy levels of ground state Energy levels of excited state Energy sublevels

5. A primitive rule: Molecular spectra - wide bands Atomic spectra - narrow lines

6. Na 1s 2 2s 2 2p 6 3s 1

7. E(eV) E=h /c N0N0 N* Flame Temperature Butane-air <2200 Acetylene-air 2400-2600 Acetylene- N 2 O 2900-3100 Acetylene- O 2 3300-3400

9. Line Monochromator bandwidth

11. Auxilary oxidant Oxidant Sample capillary Nebulizer Adjusting knob