Neglecting the spin of the proton, the angular momentum of hydrogen is given by the electron spin \( \vec{S} \) and the orbital angular momentum \( \vec{L} \). We define a total angular a. Remind yourself of the standard notation for this. We denote \( L=0,1,2,3, \ldots \) by letters \( S, P, D, F, G, \ldots \) and then alphabetically. Then we write a "term symbol" \( 2 S+1 L_{J} \). For example, \( { }^{2} S_{1 / 2} \) means \( S=1 / 2, L=0, J=1 / 2 \). This could be the ground state. b. Show that the operator \( \vec{L} \cdot \vec{S} \) commutes with \( L^{2}, S^{2} \) and \( \vec{J} \) c. Suppose \( L=2 \) and \( S=1 / 2 \). What values can the total angular momentum \( J \) assume? Write the corresponding term symbols. For each of them, what are the possible eigenvalues of \( J_{z} \) ? d. Use a table of Clebsch-Gordan coefficients to construct the states \( \left|\frac{5}{2}, \frac{3}{2}\right\rangle,\left|\frac{5}{2}, \frac{1}{2}\right\rangle,\left|\frac{5}{2},-\frac{5}{2}\right\rangle \) from the eigenfunctions \( \left|L, L_{z}\right\rangle \) of orbital angular momentum and \( \mid \uparrow \) \rangle,\( |\downarrow\rangle \) of the electron spin.