[Wien] Spin Susceptibility (Manual Version 21.1)

[Peter Blaha]

Dear Gerhard,

I agree, this equation is not correct, it will be changed in the next 
version.

Using your equation I can reproduce the Cu result of the JPCC paper and 
also a few others.
However, for some unknown reasons, I get very different results for Mo, 
and quite different for Cs, Ba and V, leading to a large improvement for 
Mo and Ba, but worsening for Cs and V.

We use just the field as an energy and shift spin-up vs. dn potentials.

Still no idea why Cu became paramagnetic.

Regards and many thanks for the report
Peter

Am 24.05.2022 um 11:58 schrieb Fecher, Gerhard:
> Dear Peter and Robert,
> I was wondering about the equation (5.1) for the spin susceptibility given on page 100 of the manual
> 
> For the molar suceptibility, one should not need to divide by the volume, and the factor 6.258116 is strange to me.
> The equation seems to not reflect the results published in J Phys Chem C 119 (2015) 19390.
> 
> I guess it should be
>          chi_s [cm^3/mol] = 0.5584939 *m[mu_B] / B[T]
> if I got the involved values for the physical constants correct to convert from atomic units to cgs.
> This reproduces the result for the molar suceptibility that I tested for Cu at a field of 200 T that is 11.17 x 10^-6 cm^3/mol.
> (Note: conversion of susceptibility chi[SI]=4*pi*chi[cgs], care may also be taken for which type of cell the calculation took place, in case of centered cells.)
> 
> The volume susceptibility, which is dimensionless in SI units, is given by
> chi_V = M/H = m / (H * V)  =  (m *mu_0) / (B * V)
> M=m/V  magnetisation = magnetic moment m per volume V, H magnetic field, induction B = mu_0 * H,  mu_0 vacuum permeability
> (conversion of vacuum permeability from cgs to SI = 4*pi *10^-7, in SI system M and H have the same physical unit A/m !)
> Further, one needs because of chi_mol = chi_V * m_m / rho
> m_m / rho = N_A * V     (m_m = mass, rho = mass density, N_A = Avogadro constant)
> such that the V cancels out in the equation for the molar susceptibility.
> 
> 
> 
> Additional questions:
> 
> Does the programm use internally the magnetic induction in Tesla or the field as an energy in Ry  (B*mu_B) ?
> 
> Do you have meanwhile any idea why Cu in the above paper became paramagnetic (chi>0)  instead of diamagnetic (chi<0) ?
> 
> Hope I have no typos.
> 
> Ciao
> Gerhard
> 
> DEEP THOUGHT in D. Adams; Hitchhikers Guide to the Galaxy:
> "I think the problem, to be quite honest with you,
> is that you have never actually known what the question is."
> 
> ====================================
> Dr. Gerhard H. Fecher
> Institut of Physics
> Johannes Gutenberg - University
> 55099 Mainz
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Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna
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