The ABINIT Users Mailing List ( CLOSED )

[joukj@hrem.stm.tudelft.nl (Jacob (=Jouk) Jansen)]

liuyudong97@mails.tsinghua.edu.cn wrote on 30-JUN-2004 15:08:34.34

>Dears all:
>I wish to know the charge density of an isolated atom, namely the atoms are 
>infinite far from each other. 
>I guess that Abinit must have such a database of charge density for each 
>element, because the command "densty " CAN give "a rough description of the 
>initial GS density, for each type of atom" .
>Is it possible to get the charge density of an isolated atom for each 
>element without any SCF calculation? 
>1)If yes, how to read out the data? 
>2)If no, it is necessary to setup a big supercell to get charge density of 
>one atoms by simulating the lesson 1 of Abinit Tutorial?
>Hopefully wish the first case is possible. 

Charge density of atoms is very important in X-ray diffraction since the
photons are scattered by the electron cloud. Already in the 1950's
calculations (mainly Hartree-Fock type) were performed to calculate them.
Later they were improved. Everything is tabelised. Since X-ray is a
diffraction technique everything is tabelised in reciprocal (Fourier) space
and are called The atomic scattering factors, f(h). The charge density is
just related to the Fourier transform of this function.
 See i.e. International Tables for Crystallography Volume C (second edition)
 p548-589, International Union of Crystallography (1999).
 

Note that you can always do option 2)  to check if both answers are equal.

             Jouk


Bush : All votes are equal but some votes are more equal than others.

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  Jouk Jansen
                 
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