STERN-GERLACH EXPERIMENT
NORTH
Collimated
beam of Ag(g)
atoms
SOUTH
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
ml
Emergent Beams
Expected
0
0
1
1
2
1,0,-1
2,1,0,-1,-2
3
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
