Negative charge problem

[cwandtj]

Hello,

This is similar problem with previous one ( viewtopic.php?f=1&t=1112 )

Files that I will discuss at here can be found from following Dropbox link:

https://www.dropbox.com/sh/qfjn35r36rg264b/bOPaAITEpU

OK... I will explain my situation. I produced cube file using Quantum Espresso to perform Bader analysis. But results seem unphysical (cube.dat).

# X Y Z CHARGE MIN DIST ATOMIC VOL
--------------------------------------------------------------------------------
1 *** *** *** -3.8564 0.8858 -27.4102
2 *** *** *** -4.8558 0.6544 -33.9104
3 *** *** *** -4.5632 0.6322 -29.9910
4 *** *** *** -4.3823 0.6484 -29.9910
5 *** *** *** -1.5105 0.8840 -8.0705
6 *** *** *** -1.5790 0.8886 -8.3151
7 *** *** *** -5.4970 0.2763 -30.4673
8 *** *** *** -1.4472 0.2207 -0.6951
9 *** *** *** -3.3471 0.2070 -15.8901
10 *** *** *** -3.3533 0.2011 -15.9480
11 *** *** *** -1.5233 0.1954 -0.7272
12 *** *** *** -1.4175 0.1725 -0.6822
13 *** *** *** -18.3069 0.2269 -185.1269
14 *** *** *** -20.2753 0.1951 -207.4078
15 *** *** *** -17.8019 0.2236 -180.5060
16 *** *** *** -15.1911 0.2627 -151.4289
17 *** *** *** -7.0110 0.2102 -70.0219
18 *** *** *** -6.5284 0.1956 -65.2208
19 *** *** *** -10.3214 0.1903 -111.0247
20 *** *** *** -12.2351 0.2135 -123.1755
21 *** *** *** -6.4149 0.2252 -63.7277
22 *** *** *** -0.5033 0.1949 -0.7144
23 *** *** *** -15.2090 0.1801 -152.3492
24 *** *** *** -20.3421 0.2137 -207.8261
25 *** *** *** -12.5439 0.1797 -128.2791
26 *** *** *** -18.7650 0.2129 -195.3277
27 *** *** *** -17.6236 0.1954 -184.1615
28 *** *** *** -10.7364 0.1793 -114.0109
29 *** *** *** -12.9055 0.1901 -130.9758
30 *** *** *** -6.9524 0.2107 -69.6487

For instance, index 13-30 are Oxygen with Z=6.

Interesting thing is that my previous trial with same element with different unitcell (this time, Rhombohedral; last time, pseudo-cubic) gives me reasonable values (cube2.dat)...

I have no idea what is going on here, and any suggestions will truly be appreciated.


Sincerely,

Chan-Woo

[graeme]

Thank you for pointing this out. The problem is that our code assumed a right-hand coordinate system. It has been fixed in version 0.28a.

[cwandtj]

That was prompt fix! Thank you! I tried the new version and it works well without any problem.

By the way, I am trying to let our group members know this update. Would you explain me more about "right-hand coordiate system"? This simly indicates that previous Bader code read only non-negative lattice vectors?

Chan-Woo

[graeme]

No, it just that we took a triple product of the lattice vectors to get the cell volume. This is positive in a right-handed coordinate system, but negative for left. I just took the absolute value (which I should have done originally).