Now whenever we see and we are going to do a pulse around the x axis, we just follow eq. For chemical shift we use WktIkz as our angle and operator. It is important to note that one spin operators only produce one spin operators. But what about two spin operators. How do we develop the rules for a bilinear term operating on Ix for example.
Bilinear operators can make two-spin order operators appear.
These will become useful as we begin to look at more complicated NMR experiments. If and commute, ie. The one spin components of an evolving product operator may be treated separately and the product of the new terms formed to obtain the result. When an operator involving only one spin is evolving under scalar coupling, the uninvolved spin operator is treated as a constant. Products involving more than one spin operator must be evaluated with care.