THE COMPLETE HOMOGENEOUS MASTER EQUATION FOR A HETERONUCLEAR 2-SPIN SYSTEM IN THE BASIS OF CARTESIAN PRODUCT OPERATORS

The complete homogeneous form of the quantum mechanical master equatio n for a heteronuclear two-spin system is presented in the basis of Car tesian product operators. The homogeneous master equation is useful si nce it allows fast, single-step computation of the density operator du ring pulse sequences, without neglecting relaxation effects. The homog eneous master equation is also a prerequisite for an expansion of the average Hamiltonian theory to include relaxation, thus forming average Liouvillian theory. The coherences of the two-spin system are assumed to be relaxed both by mutual dipole-dipole interaction and by chemica l shift anisotropy interaction with the static magnetic field. The cro ss-correlation between dipole-dipole and chemical shift anisotropy rel axation mechanisms is also considered. To illustrate the applicability of the developed formalism we simulate the overall transfer efficienc y of three different inverse detection H-1-N-15 correlation experiment s with parameters corresponding to a large protein. (C) 1998 Academic Press.