Atomic and Molecular Physics

Atomic and molecular physics is the study of atoms and molecules and it is also the field of specialization in the physics. Atomic physicists study single ions and atoms while molecular physicists even investigates very small molecules that are in their gaseous form. Atomic physicists study isolated and separated ions as well as atoms along with the excitation and electron arrangements. Addition to this the electronic excitation states which are known from the atoms and molecules which are able to rotate and as well as to vibrate. These kind of rotations and vibrations are quantized so that, there are also discrete energy levels. Therefore, the smallest energy differences exist between the different rotational states and the pure rotational spectra are far from the infrared region in which the wavelength is about 30 - 150 µm of the electromagnetic spectrum. Vibrational spectra are near to the infrared which is about 1 - 5 µm and thus the spectra resulting from electronic transitions which are mostly the ultraviolet regions.