Abstract: Optimizing phase alternating composite π pulses were described by using Wigner rotation matrix and modified Levenberg-Marquardt algorithm. The subroutines DBCLSF and QRDCMP were programed instead of "IMSL" subroutine library to solve the non-linear least square problems. The calculations were carried out on COMPAQ 586 personal computer, it was found that the optimized results were in agreement with that reported in the reference being obtained from IBM/3600 computer and better than other existing composite π pulses.

Key words: Composile pulse, Optimization, Program, Least square method