[Wien] "Best" RMT for a given total matrix size

[L. D. Marks]

I often run into problems where it is not possible to run as large an 
RKMAX as I would like, so the issue is how to choose the "best" RMT for a 
given case. I would like to suggest an idea, and others can either give 
alternative suggestions and/or point out my error.

The concept is this. For a fixed matrix size (by adjusting RKMAX 
appropriately), run a series of small calculations (e.g. a simple bulk 
material) varying the RMT's to find the lowest energy. For instance, with 
a binary AB run with RMT_B=constant-RMT_A with some steps around the 
values given by setrmt to find the lowest energy. The results appear to be 
reasonable, for instance with TiO2 this gives
 	RMT_Ti = RMT_O + 0.18

The rationalization is that in the spirit of the variational principle, 
the best RMT combination for a given size should give the lowest 
energy......

Note: if you have an old email address for me, please note that "nwu" has
been changed to "northwestern".
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Laurence Marks
Department of Materials Science and Engineering
MSE Rm 2036 Cook Hall
2225 N Campus Drive
Northwestern University
Evanston, IL 60208, USA
Tel: (847) 491-3996 Fax: (847) 491-7820
email: L-marks at northwestern dot edu
http://www.numis.northwestern.edu
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