When solving the time-independent Schrodinger equation for a spherically symmetric potential, using the separation of variables, we find that solutions of the form [tex]\psi =R(r)Y_l^m(\theta ,\phi)[/tex] where the [tex]Y_l^m[/tex] are the spherical harmonics. We apply this to the (idealized) electron in a Hydrogen atom and of course allow m to take on any integer value from [tex]-l[/tex] to [tex]+l[/tex]. However, I'm reading "Introduction to Quantum Mechanics, 2nd Ed" by Griffths and when he covers quantum scattering (by a spherically symmetric potential) he says "since we are assuming the potential is spherically symmetric, the wave function cannot depend on [tex]\phi[/tex]" (bottom of page 401). Afterwards he always assumes [tex]m=0[/tex]. I assume this is wrong?