PRINCIPLE
      Sample solution sprayed into flame
       Solvent in droplets evaporated 
           Solid residue left
    Converts to gaseous atoms(neutral atoms)
          Neutral atoms exited
   Emits color radiation to come back to ground 
              state
  When a metallic salt solution is aspirated into 
   path of flame, following events takes place
  1) Vaporization: The solvent is vaporized 
    leaving particles of solid salt. 
  2) Atomization : The salt is vaporized and 
    converted into free neutral gaseous atoms or 
    radicals 
  3) Excitation: Some of these atoms are excited 
    by the thermal energy of the flame to higher 
    energy levels.
       •   The excited metal atoms are unstable at higher energy level, and 
           quickly returns to lower energy state, while coming to lower energy 
           they emit light of their own characteristic wavelength. 
       •   The measurement emitted photons (light) forms the basis of flame 
           photometry. 
       •   The colour of the flame tells us which element is present 
           (qualitative analysis) and intensity of emitted radiation is directly 
           proportional to concentration of metallic element present in the 
           sample. 
       •   If E1 and E2 are the energy of lower and higher levels, the radiation 
           emitted during the jump is given by the equation 
                                          E2-E1 = hV ………….(1) 
                                            h = Planks constant. 
                                      V the frequency of radiation. 
                                         But V = C/ λ……………. (2) 
                                                E2-E1 = hc/ λ
                                         λ = h C / E2-E1 …………(3) 
       •   The wavelength of emitted radiation is characteristic of the atoms 
           of particular element present in the sample. It can be calculated by 
           using equation no.(3)
                      THEORY
                                  E/ kT
                      N* /No= Ae E/ kT
                      N* /No= Ae
    •
    •  N* = The number of excited atoms. 
       N* = The number of excited atoms. 
    •
    • No= The number of atoms remain in 
      No= The number of atoms remain in 
      ground state. 
      ground state. 
    •
    • A = Constant of a particular element.
      A = Constant of a particular element.
    •
    •  E= Difference in the energy level of two 
       E= Difference in the energy level of two 
      states. 
      states. 
    • K= Boltzman constant equal to R/N 
    • K= Boltzman constant equal to R/N 
    • T= Temperature of flame in Kelvin
    • T= Temperature of flame in Kelvin