Coulomb Potential Barrier: Is This Calc Right? What's fm?

[chemart]

The Coulomb potential barrier of a system of two nuclei X and Y is approximately given by VC = ZX*ZY*e2/RN where ZX and ZY are the charge numbers of the nuclei, e2 = 1.44 MeV*fm, RN = (AX1/3+AY1/3) × r0 is the sum of the nuclear radii. r0 is a constant usually estimated to 1.2 to 1.3 fm and AX and AY are the mass numbers of the nuclei. Is this right calculation? What does fm stands for?

 

[Meir Achuz]

It looks rlight. fm stands for femtometer (10^-15 meter).
The AX1/3 sands for AX to the one third power.