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<br>Dear Wien2K users,<br>
now I am going to calculate the NMR-Fermi contact
chemical shift of Li ions in the material (with magnetic Ni ions). In
the spin-polarization calculation of Wien2K. we can only obtain the
hyperfine field (HFF) near the Li nucleus. In order to get the chemical
shift, we need to get the hyperfine coupling constant A between Li and
Ni. The equation for A is A=u0(magnetic permability)*h(planck
constant)*r(nucleus gyromag ration)*g(electron g factor)*uB(Bohr
magneton)*<span style="font-family: 宋体;">ρ(spin density at the
nucleus)/(3S)(S is the spin quantum number of Ni)。If we obtained A, the
we can get the Fermi contact chemical shift</span><span style="font-size: 10.5pt; font-family: 宋体;">δ=A*</span>g*uB*S*(S+1)<span style="font-family: 宋体;">/(3*h*</span>r*KT<span style="font-family: 宋体;">), where K is Boltzmann constant</span><span style="font-family: 宋体;"> and T is temperature. Then the key question is to obtain the spin
density at or near the neclues Li. So can we directly use the the spin
density from the item "spindensities at the nucleuse(Thomson)" or the
difference between spin up and spin down electron density (RUP**-RDN**)</span><span style="font-family: 宋体;">in the scf file</span>?(I have tested this, but the calculated
chemical shift seems several orders of magnitude smaller than the
experiment value)<br><div class="ExternalClass" id="MsgContainer"><span style="font-family: 宋体;"> Furthermore, If there are two kinds of Ni ions
near the Li, the situatioin is complex. There should be two coupling
constant A1 and A2 between Li and different Ni ions. Then how to get
these two coupling constantn </span><span style="font-family: 宋体;">,
respectively</span><span style="font-family: 宋体;">? Can we first to let
one magnetic ion(for example, Ni1) to be magnetic, and force other
magnetic ion to be nonmagnetic(Ni2), and get the corresponding spin
density near the Li nucleus to calculate the corresponding A1 for Ni1,
and do the similar process for Ni2 to obtain its coupling constant A2? <br>I have browsed the mailing list archives and the userguide, but cannot find the answer. So I will much appreciate that if someone can help me.<br><br>Best
regards<br>Zhang </span></div>
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