Ground State, Ionization Energy, Optical Spectrum

1 Ground State, Ionization Energy, Optical Spectrum 

In the following E means level energy, J Internal quantum number, and g magnetic splitting 

L Martin, W.C. Bibliography on Atomic Energy Levels and Spectra, July 1968 through June 1971, NBS-SP-363 [1972] C.A. 77 [1972] No. 132561. 

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Knowledge on the plasma species can be obtained by the use of plasma diagnostics techniques, such as optical emission spectroscopy (OES) and mass spectroscopy (MS). Both techniques are able to probe atomic and molecular, neutral or ionized species present in plasmas. OES is based on measuring the light emission spectrum that arises from the relaxation of plasma species in excited energy states. MS, on the other hand, is generally based on the measurement of mass spectra of ground state species. 

In this chapter we will concentrate on the optical excitation and its theoretical treatment. This process consists of the absorption of a photon by the system of interest and the consecutive existence of the system in the excited state. We will therefore skip the reverse process, i.e. the emitting of energy reaching a lower or the ground state. We will also discard any vibrational excitations or even ionizations, which leaves us with the treatment of electronic excitations within the visible and ultraviolet region of the electromagnetic spectrum. 

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