Molecule Types Asymmetric Tops | <Prev Next> |
This object is used to describe the (magnetic)
interactions between a pair of nuclei, and one of these objects is
required for each pair of nuclei that interact. Note that this is
only partly implemented at the moment, and currently requires an I12 = I1 + I2 style coupling
scheme to be used, requiring AsNext to be set to
true for the first nucleus. For some molecules with symmetry this
limits the current implementation to interactions between
equivalent nuclei.
Note that there are multiple definitions of these terms in the literature. Various different symbols for the scalar interaction are in use, though the numerical values are the same. The definition of the dipole - dipole terms are more varied; the definition used here is as in W. G. Read and W. H. Flygare, JCP 76, 2238 (1982); doi: 10.1063/1.443297. It differs by a factor of 2 from S used for linear molecules.
Note that where x, y and z
axes are referred to below, the mapping to a, b
and c axes is determined by the representation - see Symmetry and Axis Systems so that, for
example, Dzz corresponds to Daa
in a Ir representation but Dcc in a IIIr
representation.