Radiation, emitted from orbiting electrons

Figure 4. Radiation pattern emitted from orbiting electrons when the velocities are much smaller than (A) or comparable to (B) the speed of light. (Adapted from Ref. 20.)...

AES involves the measurement of electromagnetic radiation emitted from atoms. Both qualitative and quantitative data can be obtained from this type of analysis. In the former case, the identity of different elements reflects the spectral wavelengths that are produced, while in the latter case, the intensity of the emitted radiation is related to the concentration of each element. Atomic spectra are derived from the transition of electrons from one discrete electron orbital in an atom to another. These spectra can be understood in terms of the Bohr atomic model. 

Figure 10.1 (a) Distribution of emitted radiation from an electron travelling at relativistic speeds in a circular orbit, (b) The universal, vertically integrated, synchrotron radiation spectrum as a function of reduced wavelength. The axes are calibrated for the SRS at Daresbury Laboratory... 

When X-rays are used rather than vacuum UV radiation, electrons are emitted from inner orbitals, and the spectrum obtained reflects this. These spectra also give much scope as an analytical technique. 

Niels Bohr incorporated Planck s quantum concept into Rutherford s model of the atom in 1913 to explain the discrete frequencies of radiation emitted and absorbed by atoms with one electron (H, He+, and Li2+). This electron is attracted to the positive nucleus and is closest to the nucleus at the ground state of the atom. When the electron absorbs energy, it moves into an orbit further from the nucleus and the atom is said to be in an electronically excited state. If sufficient energy is absorbed, the electron separates from the nucleus entirely, and the atom is ionized ... 

The quantum-mechanical solutions from the Schrodinger Equation utilize three quantum numbers (n, /, and mi) to describe an orbital and a fourth (ms) to describe an electron in an orbital. This model is useful for understanding the frequencies of radiation emitted and absorbed by atoms and chemical properties of atoms. 

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