[Pw_forum] Problem with PAW vs. USP

[Vic Bermudez]

Hello Giovanni,

	Thanks for your very helpful reply. For bulk Zr metal I got exactly the
same energy as you did (-614.42000823 Ry). However, my PAW energy for the
free atom is -304.20806979, which is considerably less negative than yours
and explains my erroneous cohesive energy. The only apparent difference
between our free-atom calculations is that your starting magnetization was
0.5 and mine was 1/6 = 0.1667. This shouldn't matter, and in my final result
the total magnetization was 2.00 mag. per Zr. The pseudopotentials were of
course the same for bulk Zr and the free atom.
	Your comments point to a problem with my free-atom calculation, which I
will investigate further. Thanks again. This is very helpful. Your results
also validate the PAW pseudopotential for Zr, which was my main purpose in
this exercise.

Best Wishes,
Vic Bermudez

Victor M. Bermudez
E-mail: bermudez at alum.mit.edu