|
The interaction of an electromagnetic wave with an electron bound in an atom or molecule can be described by time-dependent perturbation theory. Magnetic dipole transitions describe the dominant effect of the coupling to the magnetic part of the electromagnetic wave. They can be divided into two groups by the frequency at which they are observed: optical magnetic dipole transitions can occur at frequencies in the infrared, optical or ultraviolet between sublevels of two different electronic levels, while magnetic Resonance transitions can occur at microwave or radio frequencies between angular momentum sublevels within a single electronic level. The latter are called Electron Paramagnetic Resonance (EPR) transitions if they are associated with the electronic angular momentum of the atom or molecule and Nuclear Magnetic Resonance (NMR) transitions if they are associated with the nuclear angular momentum. == Theoretical description == The Hamiltonian of an electron bound in an atom interacting with an electromagnetic field is given by (the theoretical description follows ): The Hamiltonian can be split into a time independent and a time dependent part: with the atomic Hamiltonian and the interaction with the electromagnetic wave (time-dependent): Since the last term is quadratic in A it can be neglected for small fields. The time-dependent part can be expanded in terms belonging to electric dipole, magnetic dipole, electric quadropole and higher order terms. The term belonging to the magnetic dipole transitions is: 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「magnetic dipole transition」の詳細全文を読む スポンサード リンク
|