[Wien] large nonzero imaginary part of density matrix

[Hongjun Xiang]

Dear wien2k users,
I performed a test calculation on LaCoO3 (space group R-3c) using LSDA+U.
I found that the density matrix has large nonzero imaginary part, which 
I think
is unphysical. I search the mail list and note that Tulika Maitra 
reported a
similar problem but didn't receive any response.*
*See http://zeus.theochem.tuwien.ac.at/pipermail/wien/2006-May/007193.html

So what is the problem? Is this a bug?

Thank you.

The details of my calculation:

cat LaCoO3.dmatup
2 atom density matrix
2 0.000000 0.000000 0.000000 L, Lx,Ly,Lz in global orthogonal system
0.68853962E+00 -0.15773357E-35 0.13083373E-16 0.10862022E-18
-0.20741875E-16 -0.12892137E-16 0.27206453E+00 0.16452139E+00
0.34807065E-16 0.20601164E-16 ###########
0.13083373E-16 -0.10862022E-18 0.47624607E+00 0.10850069E-35
-0.32509490E-16 -0.26635107E-18 0.33224828E-16 0.19149350E-16
-0.27206453E+00 -0.16452139E+00
-0.20741872E-16 0.12892137E-16 -0.32509490E-16 0.26635107E-18
0.91642418E+00 0.00000000E+00 0.32509490E-16 0.26635107E-18
-0.20741872E-16 -0.12892137E-16
0.27206453E+00 -0.16452139E+00 0.33224828E-16 -0.19149350E-16
0.32509490E-16 -0.26635107E-18 0.47624607E+00 -0.10850069E-35
-0.13083373E-16 -0.10862022E-18
0.34807065E-16 -0.20601164E-16 -0.27206453E+00 0.16452139E+00
-0.20741875E-16 0.12892137E-16 -0.13083373E-16 0.10862022E-18
0.68853962E+00 0.15773357E-35

cat LaCoO3.dmatdn
2 atom density matrix
2 0.000000 0.000000 0.000000 L, Lx,Ly,Lz in global orthogonal system
0.68847085E+00 -0.45854315E-36 0.12330523E-16 0.76748517E-19
-0.23302444E-16 -0.53120543E-17 0.30510055E+00 0.65006011E-01
0.38775543E-16 0.70767826E-17 ###########
0.12330523E-16 -0.76748517E-19 0.48820635E+00 -0.24445245E-35
-0.31669939E-16 -0.34525300E-18 0.36847216E-16 0.67332825E-17
-0.30510055E+00 -0.65006011E-01
-0.23302444E-16 0.53120524E-17 -0.31669939E-16 0.34525300E-18
0.91652379E+00 0.00000000E+00 0.31669939E-16 0.34525300E-18
-0.23302444E-16 -0.53120524E-17
0.30510055E+00 -0.65006011E-01 0.36847216E-16 -0.67332825E-17
0.31669939E-16 -0.34525300E-18 0.48820635E+00 0.24445245E-35
-0.12330523E-16 -0.76748517E-19
0.38775543E-16 -0.70767826E-17 -0.30510055E+00 0.65006011E-01
-0.23302444E-16 0.53120543E-17 -0.12330523E-16 0.76748517E-19
0.68847085E+00 0.45854315E-36

My .struct file
cat LaCoO3.struct
Title
R LATTICE,NONEQUIV.ATOMS: 3167_R-3c
MODE OF CALC=RELA unit=ang
10.244834 10.244834 24.538941 90.000000 90.000000120.000000
ATOM -1: X=0.25000000 Y=0.25000000 Z=0.25000000
MULT= 2 ISPLIT= 4
-1: X=0.75000000 Y=0.75000000 Z=0.75000000
La1 NPT= 781 R0=0.00010000 RMT= 2.42 Z: 57.0
LOCAL ROT MATRIX: 1.0000000 0.0000000 0.0000000
0.0000000 1.0000000 0.0000000
0.0000000 0.0000000 1.0000000
ATOM -2: X=0.50000000 Y=0.50000000 Z=0.50000000
MULT= 2 ISPLIT= 4
-2: X=0.00000000 Y=0.00000000 Z=0.00000000
Co1 NPT= 781 R0=0.00010000 RMT= 1.91 Z: 27.0
LOCAL ROT MATRIX: 1.0000000 0.0000000 0.0000000
0.0000000 1.0000000 0.0000000
0.0000000 0.0000000 1.0000000
ATOM -3: X=0.75000001 Y=0.19800000 Z=0.30200000
MULT= 6 ISPLIT= 8
-3: X=0.24999999 Y=0.80200000 Z=0.69800000
-3: X=0.19800000 Y=0.30200000 Z=0.75000001
-3: X=0.80200000 Y=0.69800000 Z=0.24999999
-3: X=0.30200000 Y=0.75000001 Z=0.19800000
-3: X=0.69800000 Y=0.24999999 Z=0.80200000
O 1 NPT= 781 R0=0.00010000 RMT= 1.70 Z: 8.0
LOCAL ROT MATRIX: 0.0000000 0.5000000 0.8660254
0.0000000-0.8660254 0.5000000
1.0000000 0.0000000 0.0000000
12 NUMBER OF SYMMETRY OPERATIONS
1 0 0 0.00000000
0 1 0 0.00000000
0 0 1 0.00000000
1
0 0 1 0.00000000
1 0 0 0.00000000
0 1 0 0.00000000
2
0 1 0 0.00000000
0 0 1 0.00000000
1 0 0 0.00000000
3
0-1 0 0.50000000
-1 0 0 0.50000000
0 0-1 0.50000000
4
-1 0 0 0.50000000
0 0-1 0.50000000
0-1 0 0.50000000
5
0 0-1 0.50000000
0-1 0 0.50000000
-1 0 0 0.50000000
6
-1 0 0 0.00000000
0-1 0 0.00000000
0 0-1 0.00000000
7
0 0-1 0.00000000
-1 0 0 0.00000000
0-1 0 0.00000000
8
0-1 0 0.00000000
0 0-1 0.00000000
-1 0 0 0.00000000
9
0 1 0 0.50000000
1 0 0 0.50000000
0 0 1 0.50000000
10
1 0 0 0.50000000
0 0 1 0.50000000
0 1 0 0.50000000
11
0 0 1 0.50000000
0 1 0 0.50000000
1 0 0 0.50000000
12


Best regards,
Hongjun Xiang

=============================================================
 H. J. Xiang
 Postdoctoral Research Assistant
 Department of Chemistry
 North Carolina State University
 Raleigh, NC 27695-8204
 Tel: 001-919-515-8919 
 http://www4.ncsu.edu/~hxiang/
=============================================================