[Pw_forum] example 5 of example 3

[Tone Kokalj]

On Sun, Mar 21, 2004 at 04:19:09PM +0100, Goranka Bilalbegovic wrote:
> 
> When *.xsf file prepared by the pw.2.0.1 (and pw.1.3.0, 1.2.0) opens in 
> the XCrySDen, then the display of the CO molecule geometry is in the 
> default option display/unit of repetition/unit cell, and this is not 
> useful for CO. The choice of the display/unit of 
> repetition/translational asymmetric unit cell produces the correct image 
> of the CO geometry. However, the charge density is still distributed 
> according to the initial unit cell, and this is not the correct geometry.

This behavior is correct: the choice of "display/unit of repetition"
affects only the structure, but not the scalar field (charge density
in your case).

The problem here is the following: the CO molecule is positioned at
the edge of the box (unit-cell), and using a "fast 3d plot"
(output_format=5) is not very useful here (it would be when the
molecule would be positioned at the center of the box). Hence you have
two possibilities:

either: 1.) choose the coordinates of CO as:

ATOMIC_POSITIONS bohr
C 8.256 6.0 6.0
O 6.0   6.0 6.0  0 0 0

and recalculate ...

or: 2.) select the following plotting box in chdens input
(output_format=3 or 4):

    origin: -0.5 -0.5 -0.5
1st vector:  1.0  0.0  0.0
2nd vector:  0.0  1.0  0.0
3rd vector:  0.0  0.0  1.0


Regards, Tone

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| Anton Kokalj                                 Email: Tone.Kokalj at ijs.si |
| Department of Physical and Organic Chemistry Phone: x 386 1 477 3523   |
| Jozef Stefan Institute                         Fax: x 386 1 477 3811   |
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| SLOVENIA                                                               |
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