# Magnetic susceptibility in 1/eV

In this paper the authors refer to

transverse susceptibility $\chi_{ \perp}$ [meV $^{−1}$]

I was taught that the magnetic susceptibility is dimensionless.

How do I get $\chi$ in the above units??

-
In one place it is given in emu/mol, whatever that may be. –  Georg Mar 23 '11 at 22:06
Excellent question :) –  David Z Mar 23 '11 at 23:12
At any rate, whatever you were taught, it's clear that $\chi_\perp$, defined as a coefficient in equation 2 of that paper, has the unit of inverse energy, just like they indicate. $\int d^3 x$ cancels against $abc$, one time derivative cancels against $\partial_t$, the other $\partial_t$ combined with one $\hbar$ gives one energy which has to be cancelled for $S$ to have the right dimension of the other $\hbar$. So maybe you should have already asked a different question about the previous texts such as eqn 2. $\chi_\perp$ is apparently normalized differently than you think. –  Luboš Motl May 4 '11 at 11:40

Ok, this is something I didn't know. Anyway, as Georg already mentioned, the authors use the value given in emu/mol to evaluate $\chi _{\perp}$. How should I convert between these units? –  Pie86 Mar 24 '11 at 8:37