Magnetic field effects Zeeman splitting

Other types of background correction have also been developed. The Zeeman effect background correction system started gaining popularity in the early 1980s. An atomic spectral line when generated in the presence of a strong magnetic field can be split into a number of components... 

In the presence of magnetic field a further splitting into (2J+l) equispaced energy levels occurs. These correspond to the number of values that can be assumed by the magnetic quantum number M ranging from +J>M>—J (Zeeman effect). 

Figure 5.1 The effect of quadrupole interactions on an / = 3/2 nucleus in a magnetic field. The Zeeman interaction splits the levels by an equal amount, cot, (the Larmor frequency in frequency units). The central +1 /2 to -1 /2 transition is unaffected by first order coupling co j however, second order coupling, co , affects all transitions.

In 1896, Zeeman observed that application of an external magnetic field caused a splitting of atomic spectral lines. We shall consider this Zeeman effect for the hydrogen atom. We begin by reviewing magnetism. 

Evidently, Ms = 1 /2. This space quantization of s and ft, will necessarily cause the two possible electron energy states to split under the application of a magnetic field (the Zeeman Effect) the energy, E... 

The purpose of the constant magnetic field is to split the single level in two due to the nuclear Zeeman effect. The alternative electromagnetic field 5(co) facilitates transitions between sublevels. The third coil is to measure absorption. The principle difference between NMR and FRS is as follows on account of its enormous resolution, y resonance allows one to define the superfine structure investigating the transition between different nuclei states (levels) with different /, whereas NMR allows one to measure the transition... 

In practice, the emission line is split into three peaks by the magnetic field. The polariser is then used to isolate the central line which measures the absorption Ax, which also includes absorption of radiation by the analyte. The polariser is then rotated and the absorption of the background Aa is measured. The analyte absorption is given by An — Aa. A detailed discussion of the application of the Zeeman effect in atomic absorption is given in Ref. 51. 

Energy level splitting in a magnetic field is called the Zeeman effect, and the Hamiltonian of eqn (1.1) is sometimes referred to as the electron Zeeman Hamiltonian. Technically, the energy of a... 

The need for improved background correction performance has generated considerable interest in applying the Zeeman effect, where the atomic spectral line is split into several polarised components by the application of a magnetic field. With a Zeeman effect instrument background correction is performed at, or very close to, the analyte wavelength without the need for auxiliary light sources. An additional benefit is that double-beam operation is achieved with a very simple optical system. 

A further approach to correction for broad band interference utilizes the Zeeman effect. Under the effect of a strong magnetic field atomic orbitals can be split into sets with energies higher or lower than the original. The orbitals responsible for the broad band absorption remain largely unaffected. 

Figure 12.2 Magnetic field dependence of the energy levels of ortho- and para-H2. Parahydrogen (p-H2) is a singlet that is unaffected by the magnetic field, whereas orthohydrogen (o-H2) is a triplet. Its energy levels split, showing the Zeeman effect.

The magnetic hyperfine splitting, the Zeeman effect, arises from the interaction between the nuclear magnetic dipole moment and the magnetic field H at the nucleus. This interaction gives rise to six transitions the separation between the peaks in the spectrum is proportional to the magnetic field at the nucleus. 

In 1925, Wolfgang Pauli gave chemists what they wanted from the physicists a physical principle underlying electron-pair valency. Pauli built on the fact that in addition to the continuous, line, and band spectra, there is a fine structure of doublets, triplets, and multiple lines, some of which are split in a magnetic field (Zeeman effect). 

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