76 in the classical treatment the angular momentum

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Unformatted text preview: . T → ∞ statistical distribution ⇒ <cosθ> = 0 Fig. 7.6 In the classical treatment the angular momentum, and hence the magnetic moment µ, can point to any direction. The magnetization results from the average of cosθ over all atoms in the sample. Quantum mechanical treatment (7.30) ⇒ only 2J + 1 discreate values of Jz ⇒ splitting of energy levels in 2J + 1 levels. Simplest case: single electron in partially filled shell with l=0* ⇒ J = s = 1/2, gJ = g = 2 EB = ± µBB only 2 possible orientaions * In a closed shell there are always pairs of electrons with l , s and -l ,- s . Therefore the total angular spin and i i i i (7.31) orbital momentum of closed shells are zero. 7-14 Fig. 7.7 splitting of energy level of a simple spin in a magnetic field B = (0,0,B). In the low energy state the magnetic moment is parallel to the magnetic field. Fig. 7.8 fractional population of a two-level system (Fig.7.7) in thermal equilibrium at temperature T in a magnetic field B. The magnetic moment is proportional to the diffe...
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This note was uploaded on 01/19/2010 for the course MATERIALS M504 taught by Professor Adelung during the Spring '02 term at Uni Kiel.

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