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Dear All,

I have this silly question, but i am struggling to get the answer.

I generated PROCAR file for one of my calculation which gave me the occupation of each band and i used only one Kpoint for my calculation.

The problem is that i am not getting the full occupation in each band.
If the occupation of the band is 1, the sum up values come close to 1, but not to 1 exactly.

For example,
See this band number 1

-----------------------------------------------
PROCAR new format
# of k-points: 1 # of bands: 288 # of ions: 83

k-point 1 : 0.00000000 0.00000000 0.00000000 weight = 1.00000000

band 1 # energy -38.00754403 # occ. 1.00000000

ion s p d f tot
1 0.000 0.000 0.000 0.000 0.000
2 0.000 0.000 0.000 0.000 0.000
3 0.000 0.000 0.000 0.000 0.000
4 0.000 0.000 0.000 0.000 0.000
5 0.000 0.000 0.000 0.000 0.000
6 0.000 0.000 0.000 0.000 0.000
7 0.000 0.000 0.000 0.000 0.000
8 0.000 0.000 0.000 0.000 0.000
9 0.000 0.000 0.000 0.000 0.000
10 0.000 0.000 0.000 0.000 0.000
11 0.000 0.000 0.000 0.000 0.000
12 0.000 0.000 0.000 0.000 0.000
13 0.000 0.000 0.000 0.000 0.000
14 0.000 0.000 0.000 0.000 0.000
15 0.000 0.000 0.000 0.000 0.000
16 0.000 0.000 0.000 0.000 0.000
17 0.000 0.000 0.000 0.000 0.000
18 0.000 0.000 0.000 0.000 0.000
19 0.000 0.000 0.000 0.000 0.000
20 0.000 0.000 0.000 0.000 0.000
21 0.000 0.000 0.000 0.000 0.000
22 0.000 0.000 0.000 0.000 0.000
23 0.000 0.000 0.000 0.000 0.000
24 0.000 0.000 0.000 0.000 0.000
25 0.000 0.000 0.000 0.000 0.000
26 0.000 0.000 0.000 0.000 0.000
27 0.000 0.000 0.000 0.000 0.000
28 0.000 0.000 0.000 0.000 0.000
29 0.000 0.000 0.000 0.000 0.000
30 0.000 0.000 0.000 0.000 0.000
31 0.000 0.000 0.000 0.000 0.000
32 0.000 0.000 0.000 0.000 0.000
33 0.000 0.000 0.000 0.000 0.000
34 0.000 0.000 0.000 0.000 0.000
35 0.000 0.000 0.000 0.000 0.000
36 0.000 0.000 0.000 0.000 0.000
37 0.000 0.000 0.000 0.000 0.000
38 0.000 0.000 0.000 0.000 0.000
39 0.000 0.000 0.000 0.000 0.000
40 0.000 0.000 0.000 0.000 0.000
41 0.000 0.000 0.000 0.000 0.000
42 0.000 0.000 0.000 0.000 0.000
43 0.000 0.000 0.000 0.000 0.000
44 0.000 0.000 0.000 0.000 0.000
45 0.000 0.000 0.000 0.000 0.000
46 0.000 0.000 0.000 0.000 0.000
47 0.000 0.000 0.000 0.000 0.000
48 0.000 0.000 0.000 0.000 0.000
49 0.000 0.000 0.000 0.000 0.000
50 0.000 0.000 0.000 0.000 0.000
51 0.000 0.000 0.000 0.000 0.000
52 0.000 0.000 0.000 0.000 0.000
53 0.000 0.000 0.000 0.000 0.000
54 0.000 0.000 0.000 0.000 0.000
55 0.000 0.000 0.000 0.000 0.000
56 0.000 0.000 0.000 0.000 0.000
57 0.000 0.000 0.000 0.000 0.000
58 0.000 0.000 0.000 0.000 0.000
59 0.000 0.000 0.000 0.000 0.000
60 0.000 0.000 0.000 0.000 0.000
61 0.000 0.000 0.000 0.000 0.000
62 0.000 0.000 0.000 0.000 0.000
63 0.000 0.000 0.000 0.000 0.000
64 0.000 0.000 0.000 0.000 0.000
65 0.000 0.000 0.000 0.000 0.000
66 0.000 0.000 0.000 0.000 0.000
67 0.000 0.000 0.000 0.000 0.000
68 0.000 0.000 0.000 0.000 0.000
69 0.000 0.000 0.000 0.000 0.000
70 0.000 0.000 0.000 0.000 0.000
71 0.000 0.000 0.000 0.000 0.000
72 0.000 0.000 0.000 0.000 0.000
73 0.000 0.000 0.000 0.000 0.000
74 0.000 0.000 0.000 0.000 0.000
75 0.000 0.000 0.000 0.000 0.000
76 0.000 0.000 0.000 0.000 0.000
77 0.000 0.000 0.000 0.000 0.000
78 0.000 0.000 0.000 0.000 0.000
79 0.000 0.000 0.000 0.000 0.000
80 0.000 0.000 0.000 0.000 0.000
81 0.000 0.000 0.000 0.000 0.000
82 0.000 0.000 0.000 0.000 0.000
83 0.961 0.008 0.000 0.000 0.969
tot 0.962 0.009 0.000 0.000 0.971
---------------

My question is

1) The total value mentioned at the end of the band is 0.971 and
not exactly 1 and where does this 0.029 electron goes.

(If it is related to setting up a threshold how should i increase the threshold to see the remaining electron).

2) My second questions rather silly, In the S orbital of 1-82ions (in the above band) you find all 82 atoms have zero occupancy and 83 atom has the occupancy of 0.961.

But the total value is 0.962 mentioned at the bottom.
where does this 0.001 comes from.

(How should i set my incar to see more significant figures in this case).

So, to summarize, the whole band is dominated by the 83 rd ions, and the total occupation value is 0.969, but how the total values shown at the bottom differs (0.971).

The errors are negligible in this case, but, i still see some major changes in other bands and that's why i am discussing it here.

Also, how the occupation could be expected in the unoccupied bands, where there is no electron on it.

Please help me understand this PROCAR file..,

Best,
k




<span class='smallblacktext'>[ Edited ]</span>

1) please note that PROCAR gives (the sums of) the charges that are obtained by integrating the charge density in the volumes of the spheres
(with r=RWIGS) around each atom. Any space in the cell which is NOT covered by these spheres is not accounted for.
2) these are most probably rounding errors (please note that the partial charges are only written to an accuracy of me-.) even if every of the remaining atoms would have a charge of 0.0001 e- (not written because of the format !) this would sum up to 0.008
3) PROCAR gives the projected charge corresponding to the wavefunction of the state, no matter if the state is not occupied or not (please have a look at occ. to see if this state is really occupied or not in your system)