The typical separation of a directly bonded l3C-1H pair is 1.1 A. Assuming a correlation time of 20 ps (i.e. the fast motion limit), calculate values for the rate constants Rz(1), Rz(2) σ12, Rxy(1)- and Rxy(2) (take spin one to be 13C and spin two to be 'H). [If you have completed the previous exercise, then all you have to do is recognize that, in the fast motion limit, the only difference between a 1H-1H pair and a 13C-1H pair is the value of the constant b.]
Compare your answers with those in parts (b)-(d) of the previous exercise.