Indirect nuclear spin-spin couplings: *SPIN-S

This input module controls the calculation of which indirect nuclear spin-spin coupling constants and what contributions to the total spin-spin coupling constants that are to be calculated.

.ABUNDA

READ (LUCMD,*) ABUND

Set the natural abundance threshold in percent for discarding couplings between certain nuclei. By default all isotopes in the molecule with a natural abundance above this limit will be included in the list of nuclei for which spin-spin coupling constants will be calculated. Read one more line containing the abundance threshold in percent. The default value is 1.0 (i.e. 1%), which includes both protons and $^{13}$C nuclei.

.COUPLING NUCLEUS

READ (LUCMD,*) NUCSPI
READ (LUCMD,*) (IPOINT(IS), IS=1,NUCSPI)

Calculates all coupling constants in a molecule to a selected number of nuclei only. The first number NUCSPI is the number of nuclei to which couplings shall be calculated, and the next line reads in the number of the symmetry-independent nucleus as given in the MOLECULE.INP file.

.ISOTOPE

READ (LUCMD,*) (ISOTPS(IS), IS=1, NATOMS)

Calculate the indirect spin-spin coupling constants for a given isotopic constitution of the molecule. The next line reads the isotope number for each of the atoms in the molecule (including also symmetry-dependent molecules). The isotopic number for each atom is given in terms of the occurance in the list of natural abundance of the isotopes for the given atom, i.e. the most abundant isotope is number 1, the second-most abundant is number 2 and so on.

.NODSO

Do not calculate diamagnetic spin-orbit contributions to the total indirect spin-spin coupling constants. This will give wrong results for the total spin-spin couplings.

.NOFC

Do not calculate the Fermi contact contribution to the total indirect spin-spin coupling constants. This will give wrong results for the total spin-spin couplings.

.NOPSO

Do not calculate the paramagnetic spin-orbit contribution to the indirect spin-spin coupling constants. This will give wrong results for the total spin-spin couplings.

.NOSD

Do not calculate the spin-dipole contribution to the total indirect spin-spin coupling constants. This will give wrong results for the total spin-spin couplings.

.PRINT

READ (LUCMD,*) ISPPRI

Set the print level in the output of the final results from the spin-spin coupling constants. In order to get all individual tensor components (in a.u.), a print level of at least 5 is needed. Read one more line containing the print level. Default value is the value of IPRDEF from the general input module.

.SD+FC

Do not split the spin-dipole and Fermi contact contributions in the calculations.

.SDxFC ONLY

Will only calculate the spin dipole-Fermi contact cross term, and the Fermi contact-Fermi contact contribution for the triplet responses. The first of these two terms only contribute to the anistotropy, and one may in this way obtain the most important triplet contributions to the isotropic and anisotropic spin-spin couplings by only solving one instead of seven response equations for each nucleus.

.SELECT

READ (LUCMD,*) NPERT
READ (LUCMD, *) (IPOINT(I), I = 1, NPERT)

Select which symmetry-independent nuclei for which indirect nuclear spin-spin couplings is to be calculated. This option will override any selection based on natural abundance (the .ABUNDA keyword), and at least one isotope of the nuclei requested will be evaluated (even though the most abundant isotope with a non-zero spin has a lower natural abundance than the abundance threshold). Read one more line containing the number of nuclei selected, and another line with their number (sorted after the input order). By default, all nuclei with an isotope with non-zero spin and with a natural abundance larger than the threshold will be included in the list of nuclei for which indirect spin-spin couplings will be calculated.