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Homework Statement
Show that the rotational wavefunction 3cos2? -1 is an eigenfunction of the
Hamiltonian for a three dimensional rigid rotor. Determine the corresponding eigenvalue.
Homework Equations
the eigenstates are |l,m>
the quantum number of the total angular momentum is l
the quantum number along the z-axis is m
L^2|l,m>=l(l+1)|l,m>, where l=0,1/2,1,3/2...
L_z|l,m>=m|l,m>,where m=-l,-(l,-1),...,l-1,l
-l[tex]\leq[/tex]m[tex]\leq[/tex]l
The Attempt at a Solution
H should=L^2/(2I) but not in 3D, so I need to put the position and momentum operators into components: L[tex]_{x}[/tex]=YP[tex]_{z}[/tex]-ZP[tex]_{y}[/tex]
L[tex]_{y}[/tex]=ZP[tex]_{x}[/tex]-XP[tex]_{z}[/tex]
L[tex]_{z}[/tex]=XP[tex]_{y}[/tex]-YP[tex]_{x}[/tex]
and {L[tex]^{2}[/tex],L[tex]_{x,y,z}[/tex]=0
if we call the eigenstates |[tex]\alpha[/tex],[tex]\beta[/tex]>
the eigenvalue of L[tex]^{2}[/tex]is L[tex]^{2}[/tex]|[tex]\alpha,\beta[/tex]>=[tex]\hbar^{2}[/tex][tex]\alpha[/tex],[tex]\beta[/tex]>=[tex]\hbar^{2}[/tex][tex]\alpha[/tex]