The Expectation Value of \bgroup\color{black}$L_x$\egroup

What is the expectation value of \bgroup\color{black}$L_x$\egroup in the state \bgroup\color{black}$\psi(\vec{r})=R(r)(\sqrt{2\over 3}Y_{11}(\theta,\phi)-\sqrt{1\over 3}Y_{10}(\theta,\phi))$\egroup?

We need \bgroup\color{black}$L_x=(L_++L_-)/2$\egroup.

\begin{eqnarray*}
\langle\psi\vert L_x\vert\psi\rangle
&=&{1\over 2}\left<\sq...
...t> \\
&=&{\hbar\over 2}{2\over 3}(-1-1)=-{2\over 3}\hbar \\
\end{eqnarray*}




Jim Branson 2013-04-22