Hi, 1. The problem statement, all variables and given/known data A particle of mass m has a potential V(r)= -Vo r<a 0 r>a Find the minimum value of Vo for which there's a bound state of energy and angular momentum are zero by solving shrodinger equation for E<0 and taking the limit E-> 0 2. Relevant equations 3. The attempt at a solution I want to know what does l represent in the radial shrodinger equation ? Is it the angular momentum ? For now, I considered l=0 and solved Shrodinger equation I got r<a u(r)=C*sin(βr) with β=sqrt(2m(Vo+E)/h²) r>a u(r)=Bexp(-kr) with k= sqrt(-2mE/h²) With boundary conditions we have -β/k=tan(βa) Where am I supposed to use E->0 ..? Is it just in β=sqrt(2m(Vo+E)/h²) so that Vo=β²h²/2m ?