1. A method of synthesizing pulses for a given selective excitation profile in a system including at least one of a two-level quantum system and a subsystem described by the spin domain Bloch equation, comprising the steps of: determining frequency envelopes to produce the given selective excitation profile; producing a plurality of solutions via an inverse scattering transform producing said envelopes, including identifying and producing a minimum energy solution to said inverse scattering transform for pulses that generate the given selective excitation profile; and generating pulses corresponding to any of the plurality of solutions to produce the envelopes that produce said given selective excitation profile.