If the parent molecule has
nNuclei non zero, then
each state will have
nNuclei
of the items listed below (TAsymmetricTopNucleus). The following
coupling scheme is normally used:
F1
= J1 + I1; F2 = F1 + I2; ... F = Fn-1 + In
though an alternative scheme must be used for equivalent nuclei,
as described under the
AsNext
setting.
Note that only nuclei not explicitly simulated with nucleus
objects should be included in calculating the statistical
weights (eeWt and so
on). If all equivalent nuclei have been explicitly included,
then the statistical weights should be calculated as if there
were an additional pair of equivalent spin zero nuclei, which
will mean some mean weighs will be zero. A simple check for
correct operation is to compare the rotational structure with
and without the nuclei explicitly included, with the weights
calculated in the latter case including all nuclei. If the
linewidth is set somewhat larger than the width of the hyperfine
structure the spectra should appear identical.
For interactions between nuclei see Nuclear Spin - Nuclear Spin
Coupling
Settings
Note that these two should be set at the molecule level, but are
in fact implemented at the state level, with any change in these
two properties copied to all the states in the molecule.
Spin |
Nuclear spin. (Note that this setting should logically
be at the molecule, rather than the state level. Changing
a spin here will change the corresponding spins in any
other states.) |
AsNext |
Set to indicate that this nucleus is equivalent to the
following nucleus. This is required for molecules with a
centre of symmetry, where nuclei not on the centre of
symmetry must occur as equivalent pairs. In these
circumstances all parameters are taken from the second of
the two nuclei, and the modified coupling scheme:
I12 = I1 + I2; F = J + I12
is used. This setting can also be used for molecules
without low symmetry (C1, Ci, Cs),
in which case the alternate coupling scheme is used but
the nuclei are not forced to be identical. Note that equivalent nuclei
are not currently implemented for D2 and D2h
symmetry.
|
MaxDJ |
Maximum ΔJ to include to
consider in evaluating matrix elements for this nucleus.
Default is negative, which includes all possible matrix
elements, but setting this to zero (or possibly 1) can
give significantly faster calculations but may be less
accurate, particularly for low J. |
Parameters
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, CHIzz corresponds to χaa in a Ir
representation but χcc in a IIIr
representation.
aF |
Nuclear spin - electron spin Fermi Contact interaction
(I.S). |
Tzz |
Tzz = -(Txx+Tyy) component of Nuclear spin - electron
spin dipole dipole interaction. |
Txxmyy |
Txx-Tyy component of Nuclear spin - electron spin dipole
dipole interaction. |
Tab |
ab component of Nuclear spin - electron spin dipole
dipole interaction. |
Tac |
ac component of Nuclear spin - electron spin dipole
dipole interaction. |
Tbc |
bc component of Nuclear spin - electron spin dipole
dipole interaction. |
CHIzz |
zz component of Nuclear Quadrupole interaction. |
CHIxxmyy |
xx-yy component of Nuclear Quadrupole interaction. |
CHIab |
ab component of Nuclear Quadrupole interaction. |
CHIac |
ac component of Nuclear Quadrupole interaction. |
CHIbc |
bc component of Nuclear Quadrupole interaction. |
Caa |
aa component of Nuclear Spin - Rotation interaction. |
Cbb |
bb component of Nuclear Spin - Rotation interaction. |
Ccc |
cc component of Nuclear Spin - Rotation interaction. |