stern- gerlach experiment
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Transcript of stern- gerlach experiment
STERN-GERLACH EXPERIMENT
NORTH
SOUTHCollimated beam of Ag(g)atoms Magnetic Field
Z-direction ↑
STERN-GERLACH EXPERIMENT After passing through the magnetic field two
beams of Ag(g) atoms emerge – suggests that some sort of quantized angular momentum is associated with a charged particle (classically a range of deflections is expected). Can the deflection be due to an electron? Can the deflection be due, in particular, to orbital angular momentum?
STERN-GERLACH EXPERIMENT Silver has an odd number of electrons. The
usual table of l and ml values shows that orbital angular momentum cannot explain the Stern Gerlach experiment for Ag(g).
l mlEmergent Beams Expected
0 0 11 1,0,-1 32 2,1,0,-1,-2 5
STERN-GERLACH EXPERIMENT Neglecting history, we can write an electron
configuration for neutral Ag which also suggests that orbital angular momentum cannot account for the Stern Gerlach expt.
Ag: [Ar] 3d104s24p64d105s1
The lone electron is in an s orbital for which l = 0.
STERN-GERLACH EXPERIMENT FOR Ag
Again, for the lone unpaired electron in Ag we have l = 0.
Magnitude of orbital angular momentum “squared” = l (l +1)ħ2 = 0
Similarly LZ = ml ħ = 0 The z-component of angular momentum
determines how many “beams” we should see in the Stern-Gerlach experiment.
STERN-GERLACH EXPERIMENT
SPIN WAVE FUNCTIONS