[Re:17] Regarding afm fcc-Fe convergance and higher total energy values compared to bcc fm-Fe

Posted on : February 23, 2019 (Sat) 03:46:47

by Qais Ali

Dear Hitoshi GOMI,

Thank you for very helping comments and answers to my queries.
Related to FCC Fe calculations I made two files one with single atom with following input;
c------------------------------
go data/test_1
c brvtyp a c/a b/a alpha beta gamma
fcc 6.23,1,,,,,
c-----------------------------
c edelt ewidth reltyp sdftyp magtyp record
0.001 1.0 nrl mjw mag init
c------------------------------------------------------------
c outtyp bzqlty maxitr pmix
update 3 300 0.035
c------------------------------------------------------------
c ntyp
1
c------------------------------------------------------------
c type ncmp rmt field mxl anclr conc
Fe1 1 0.35355 0.0 2
26 100
c------------------------------------------------------------
c natm
1
c------------------------------------------------------------
c atmicx(in the unit of a) atmtyp
0 0 0 Fe1
c-----------------------------------------------------------

And second file with four atoms as shown below;

c------------------------------
go data/test_4
c brvtyp a c/a b/a alpha beta gamma
sc 6.23,1,,,,,
c-----------------------------
c edelt ewidth reltyp sdftyp magtyp record
0.001 1.0 nrl mjw mag init
c------------------------------------------------------------
c outtyp bzqlty maxitr pmix
update 3 300 0.035
c------------------------------------------------------------
c ntyp
4
c------------------------------------------------------------
c type ncmp rmt field mxl anclr conc
Fe1 1 0.35355 0.0 2
26 100
Fe2 1 0.35355 0.0 2
26 100
Fe3 1 0.35355 0.0 2
26 100
Fe4 1 0.35355 0.0 2
26 100
c------------------------------------------------------------
c natm
4
c------------------------------------------------------------
c atmicx(in the unit of a) atmtyp
0 0 0 Fe1
0.5 0 0.5 Fe2
0.5 0.5 0 Fe3
0 0.5 0.5 Fe4
c-----------------------------------------------------------

I expect that total energy per atom for both of these cases remains same, however, there exists an energy difference of ~62meV between them, so can you please identify mistake or the reason for this difference? I shall be thankful for your helpful reply.

Regards,
Qais Ali