Dear colleagues,
I am a bit desperate and I hope I can get some help here. I am trying to calculate the hyperfine coupling for a Np compound using orca. There is a slight problem, orca does not seem to have any data stored for Np nuclei. I have tried getting help from the orca mailing list numerous times, but I have received no answer. So I thought I give it a go here.
Although parameters for Np are not present in orca, they can be handed over to the program like this:
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# In addition you can change several parameters
# e.g. for a different isotope.
Nuclei = all N { PPP=39.1, QQQ=0.5, III=1.0 };
# PPP : the proportionality factor for this nucleus
# = ge*gN*betaE*betaN
# QQQ : the quadrupole moment for this nucleus
# III : the spin for this nucleus
III for the nucleus is simple, also the quadrupole moment has to be given in barn and I can find that value. I have trouble with this "proportionality factor" from the given equation, gN seems to be the magnetic moment for the Np nucleus. This I find in e.g. the CRC handbook of Chemistry and Physics to be 3.14 nuclear magnetons. I am not sure at all how to proceed from here. The unit expected by orca is MHz/au**3 , and I am not sure how to transform the values. betaN could be the nuclear magneton for the proton (betaN = 5.05 * 10^-27 J/T or maybe it is beta for Np which could be calculated via betaN = e*\hbar / 2m_N where m_N would be the mass for the Np nucleus.
The nuclear magneton in atomic units is 2.723 * 10^-4 This makes me wonder where the MHz enters into the PPP factor and why we would have the atomic units cubed!
Having no information what kind of input is expected it is hard to figure out how to calculate the PPP factor. The only thing I have to go on is the value for 14N from the input example above. The problem is, the betaN value for this nucleus is 0.404. And I do not get to a value of 39.1 MHz/au**3 as given in the manual.
I would very much appreciate any help in the matter and I thank you for your patience reading this slightly of topic question.
Kind regards,
Michael