Dear all,
I have found a problem with the number of atoms resulting in a
computation with pw.x. The essentials of the geometry specification are:
&SYSTEM
space_group=155, rhombohedral=.TRUE.
A=8.7018, B=8.7018, C=8.7018
cosAB=-0.0032742, cosAC=-0.0032742, cosBC=-0.0032742
nat=13, ntyp=4
...
/
ATOMIC_POSITIONS crystal_sg
V 0.00000 0.00000 0.00000
Ge -0.75399 -0.99800 -0.74920
N -0.73084 -0.51728 -0.00123
N -0.01635 -0.01149 -0.23613
N -0.52047 -0.23372 -0.50080
N -0.22951 -0.73368 -0.74864
N -0.26226 -0.48504 -0.98625
Sn -0.12491 -0.62544 -0.12283
Ge 0.00000 -0.49511 -0.50488
Ge -0.50000 -0.75534 -0.24466
Sn -0.50000 -0.24993 -0.75007
N -0.76700 -0.76700 -0.76700
Sn -0.62767 -0.62767 -0.62767
With this input I expect to have 56 atoms, as corresponds to a V-doped
(Ge,Sn) spinel nitride having almost the same number of Ge and Sn atoms
(in fact, there is one Sn atom less) as I have verified independently.
However, I obtain at the beginning of the pw.x calculation the following
list of atoms:
site n. atom positions (alat units)
1 V tau( 1) = ( 0.0000000 0.0000000 0.0000000 )
2 Ge tau( 2) = ( -0.0033926 -0.2015179 0.2870436 )
3 Ge tau( 3) = ( 0.1762159 0.0978209 0.2870436 )
4 Ge tau( 4) = ( -0.1728234 0.1036970 0.2870436 )
5 Ge tau( 5) = ( -0.0033926 0.2015179 1.4393268 )
6 Ge tau( 6) = ( 0.1762159 -0.0978209 1.4393268 )
7 Ge tau( 7) = ( -0.1728234 -0.1036970 1.4393268 )
8 N tau( 8) = ( -0.5167561 -0.1236930 1.0074235 )
9 N tau( 9) = ( 0.3654993 -0.3856774 1.0074235 )
10 N tau( 10) = ( 0.1512567 0.5093704 1.0074235 )
11 N tau( 11) = ( -0.5167561 0.1236930 0.7189470 )
12 N tau( 12) = ( 0.3654993 0.3856774 0.7189470 )
13 N tau( 13) = ( 0.1512567 -0.5093704 0.7189470 )
14 N tau( 14) = ( 0.1556621 0.0938462 1.5744671 )
15 N tau( 15) = ( -0.1591043 0.0878842 1.5744671 )
16 N tau( 16) = ( 0.0034422 -0.1817305 1.5744671 )
17 N tau( 17) = ( 0.1556621 -0.0938462 0.1519033 )
18 N tau( 18) = ( -0.1591043 -0.0878842 0.1519033 )
19 N tau( 19) = ( 0.0034422 0.1817305 0.1519033 )
20 N tau( 20) = ( -0.0139315 0.2264700 1.0041779 )
21 N tau( 21) = ( -0.1891630 -0.1253001 1.0041779 )
22 N tau( 22) = ( 0.2030945 -0.1011699 1.0041779 )
23 N tau( 23) = ( -0.0139315 -0.2264700 0.7221925 )
24 N tau( 24) = ( -0.1891630 0.1253001 0.7221925 )
25 N tau( 25) = ( 0.2030945 0.1011699 0.7221925 )
26 N tau( 26) = ( 0.3676808 -0.2000458 0.7412862 )
27 N tau( 27) = ( -0.0105956 0.4184438 0.7412862 )
28 N tau( 28) = ( -0.3570852 -0.2183980 0.7412862 )
29 N tau( 29) = ( 0.3676808 0.2000458 0.9850842 )
30 N tau( 30) = ( -0.0105956 -0.4184438 0.9850842 )
31 N tau( 31) = ( -0.3570852 0.2183980 0.9850842 )
32 N tau( 32) = ( 0.5127756 0.1138545 0.7287873 )
33 N tau( 33) = ( -0.3549887 0.3871495 0.7287873 )
34 N tau( 34) = ( -0.1577869 -0.5010040 0.7287873 )
35 N tau( 35) = ( 0.5127756 -0.1138545 0.9975831 )
36 N tau( 36) = ( -0.3549887 -0.3871495 0.9975831 )
37 N tau( 37) = ( -0.1577869 0.5010040 0.9975831 )
38 Sn tau( 38) = ( -0.0014732 -0.4102001 1.2238930 )
39 Sn tau( 39) = ( 0.3559803 0.2038242 1.2238930 )
40 Sn tau( 40) = ( -0.3545071 0.2063759 1.2238930 )
41 Sn tau( 41) = ( -0.0014732 0.4102001 0.5024774 )
42 Sn tau( 42) = ( 0.3559803 -0.2038242 0.5024774 )
43 Sn tau( 43) = ( -0.3545071 -0.2063759 0.5024774 )
44 Ge tau( 44) = ( -0.3506754 0.2104528 0.5754626 )
45 Ge tau( 45) = ( -0.0069197 -0.4089202 0.5754626 )
46 Ge tau( 46) = ( 0.3575951 0.1984674 0.5754626 )
47 Ge tau( 47) = ( 0.3575880 0.1984633 0.5754510 )
48 Ge tau( 48) = ( -0.0069197 -0.4089120 0.5754510 )
49 Ge tau( 49) = ( -0.3506683 0.2104487 0.5754510 )
50 Ge tau( 50) = ( -0.1808480 0.3132379 0.8631852 )
51 Ge tau( 51) = ( 0.3616960 -0.0000000 0.8631852 )
52 Ge tau( 52) = ( -0.1808480 -0.3132379 0.8631852 )
53 Sn tau( 53) = ( 0.1771154 -0.3067729 0.8631852 )
54 Sn tau( 54) = ( -0.3542309 -0.0000000 0.8631852 )
55 Sn tau( 55) = ( 0.1771154 0.3067729 0.8631852 )
56 N tau( 56) = ( 0.0000000 -0.0000000 0.4022443 )
57 N tau( 57) = ( -0.0000000 -0.0000000 1.3241261 )
58 Sn tau( 58) = ( -0.0000000 -0.0000000 0.6427795 )
59 Sn tau( 59) = ( 0.0000000 -0.0000000 1.0835909 )
i.e. there are 3 Ge atoms more than expected (the count for the other
atoms is OK). And one can see that atoms 44/49, 45/48 and 46/47 are at
nearly the same positions. But of course with these positions added
automatically by pw.x the calculation cannot progress. How can this have
happened? There is something wrong here.
Best regards,
--
José C. Conesa
Research Professor
Instituto de Catálisis y Petroleoquímica, CSIC
Marie Curie, 2; Campus de Cantoblanco
28028 Madrid (Spain)
Telef. +34 915854766
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