318 SOLUTIONSa)ForS = 0 the two electrons are in a spin singlet which has odd parity.
Hence, the orbital state must have even parity. The initial and final orbital
wave functions are given below, along with the form of the matrixelement.
The relative coordinate isr:The matrix element has two factors.b) For S = 1 the spins are in a triplet state which has even parity. The
orbitalpart of the wave function has odd parity. There is a minus sign
between the two terms in (S.5.66.4) instead of a plus sign, and ditto for the
final wave function. Now the differential cross section is
There is a relative minussign between the two term in the matrix element.
5.67 Spin-Dependent Potentials (Princeton)
In the first Born approximation the scattering is proportional to the square
of the matrix element between initial and final states. If the initial wave
vector is and the final one is set and evaluate