1. The problem statement, all variables and given/known data The atomic nucleus of Deuterium is a bound state of two nucleons. Through a change of coordinates we can transform the situation into a central force problem with a potential described by -V0 for r > R and 0 for r < R. In the ground state of this nucleus the angular momentum number is l=0. Find the binding energy of the nucleons. 2. Relevant equations The radial equation: http://en.wikipedia.org/wiki/Partic...c_potential#Derivation_of_the_radial_equation 3. The attempt at a solution I have two (second degree) radial equations (inside and outside of R) with different E, both with l = 0. I also have two conditions at r = R, where the two solutions and their derivatives have to be equal. I also have the normalization condition. That makes three constraints for four constants (plus the energy), so I can't solve it. I've tried adding the condition that ψ(0) = 0, because the nucleons can't be in the same place. This would allow me to find the energy inside R, which I think would be the end of the problem (since I am just asked to find the binding energy), but I'm not sure it is right, especially because doing it like this I get a solution with no dependence of V0. Can you tell me how to continue from here? Thank you for your time.