I had to ponder this question some time ago. I think the difference here is the same as between Ry and Ha energy units, so that in the "convention" that QE uses an extra 1/2 proliferates into the mass units as well.
But this is my guess, which may not be the ultimate truth. Actually, considering how many times I get my butt handed back to me in this forum, I could be totally wrong about it. Cheers, S. Cristian Degli Esposti Boschi wrote: > > Am I right? Why the 1/2 factor? > > And what are the typical units used for force constants? -- ********************************************************* Serge M. Nakhmanson phone: (630) 252-5205 Assistant Scientist fax: (630) 252-4798 MSD-212, Rm. C-224 Argonne National Laboratory 9700 S. Cass Ave. Argonne, IL 60439 *********************************************************
