Atomic Emission Spectrometry (AES):

In this technique, a sample is generally excited through the thermal energy of argon plasma, flame, or an electrical discharge. The atoms within the sample absorb thermal energy and causing the excitation of the outer orbital electrons. As the excited state is short lived and the excited atoms return back to the ground state after an extremely short lifetime (typically 10^-6 to 10^-9 s). This is accompanied through the emission of electromagnetic radiation, generally in the form of light in the UV - VIS region. A wavelength of the emitted radiation and its intensity gives the qualitative and quantitative data about the analyte. An atomic emission spectroscopy employing flame as a means of excitation is known as flame photometry or flame emission spectroscopy (FES). It is used for the routine determination of metals, majorly of alkali and alkaline earth metals, by other metals could also be analysed.