[Wien] Spin Susceptibility (Manual Version 21.1)

[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."

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Dr. Gerhard H. Fecher
Institut of Physics
Johannes Gutenberg - University
55099 Mainz
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