> Dear Macros,
>
> Thank you for your detailed explanation. Maybe my question is not very
> unambiguous in my previous mail.
Indeed...
> In fact, I want to know who is the major contributor to the stability of
> a certain sytem, such as to its ground state total energy. For Pt, Is
> the 5dx2-y2 atomic orbital, 5dxy, or the 5dz2 orbital? In addition, can
> the different space direction of these atomic orbital affect the
> structural stability of a sytem? Thanks again for your help.
That would depend on the structure of your metal. I don't remember exactly
the structure of Pt, but suppose that it is in a fcc structure, and take a
cubic cell. Then, the $d_{xz,xy,yz}$-orbitals, which would form covalent
(thus strong) bonds, would be pointing towards nearest-neighbors and
forming bonds, while the $z^2$ and $x^2-y^2$ would be pointing towards
nnn, and then would not be the main contributors to the stability of the
system, from a bonding point of view. If the structure were simple cubic,
then we would have the reverse situation: the two latter would be pointing
towards nn, and then they would be the ones to contribute the most. Of
course that's all from the point of view of physical argumentations in a
LCAO framework, but that's what siesta is all about, in the end... :)
However, I guess that you might want to know what the contribution is,
from DFT, to the bonding. In this case, I would not know exactly how to
proceed. Maybe some more experienced users in the list could give you some
advice on that, or maybe you can find some enlightenment in David G.
Pettifor's book "Bonding and Structure of Molecules and Solids", and in
Harrison's books on electronic structure.
Cheers,
Marcos
>
> Best regards,
> C.H. Hu
>
> On 5/23/07, Marcos Verissimo Alves <[EMAIL PROTECTED]> wrote:
>>
>> From your attachment I would guess you are using a DZP basis set for the
>> 6s orbitals, and a DZ basis set for the d orbitals (this can be checked
>> in
>> the output file, a bit before the calculation starts), right? So, after
>> the two lines listing the atomic orbitals:
>>
>> 6s 6s 6py 6pz 6px 5dxy 5dyz
>> 5dz2
>> 5dxz 5dx2-y2 5dxy 5dyz 5dz2 5dxz 5dx2-y2
>>
>> you have the following entry:
>>
>> 1 4.729 0.268 0.145 0.053 0.043 0.095 0.638 0.894
>> 0.562
>> 0.609 0.534 0.205 0.040 0.204 0.204 0.235
>>
>> The first number refers to the atom number - let's call it iat - in the
>> list of atoms (in the line above, iat=1). The second is the total
>> Mulliken
>> charge on atom iat (4.729). Then, in the first line, you have the
>> Mulliken
>> charge due to the first zeta of orbital 6s, the (Mulliken) charge due to
>> the second zeta of orbital 6s, and the charge due to the polarization
>> orbitals, which are 6p orbitals. Following, the charge due to the 1st
>> zeta
>> of 5dxy, 5dyz and 5dz2, respectively. On the second line, you have the
>> charge due to the first zetas of 5dxz and 5dx2-y2, and finally the last
>> four numbers are the charges due to the second zetas of the 5dxy, 5dyz,
>> 5dz2, 5dxz, 5dx2-y2.
>>
>> So, to have the total charge on a given orbital, just sum the charges due
>> to the zetas. To get the charge due to d-electrons only, you would sum
>> the
>> charges over all d-orbitals and zetas. To get the charge due to the
>> s-states, you will have to sum also over the 6p-orbitals. This is
>> because,
>> as stated in the siesta manual, although you have no 6p orbitals
>> explicitly, they are the higher angular-momentum solution to the problem
>> of a 6s orbital in a weak electric field (that is, they are the
>> polarization orbitals as defined in siesta). Therefore, they also
>> contribute to the s-orbitals' charge. (Please someone correct me if I'm
>> wrong...)
>>
>> Hope this helps you. Cheers,
>>
>> Marcos
>>
>>
>> > Dear Siester users,
>> >
>> > I got the results of Mulliken charge (see my attachment), but how to
>> > evaluate the contribution of different atomic orbitals? My system is
>> > Platinum (Pt, 5d96s1). Is the main attributor to its stability 5dx2-y2,
>> > 5dxy, or 5dz2?
>> >
>> > Thanks in advance!
>> >
>> > Best regards,
>> > C. H. Hu
>> >
>>
>>
>> --
>> Dr. Marcos Verissimo Alves
>> Post-Doctoral Fellow
>> Condensed Matter and Statistical Physics Sector
>> International Centre for Theoretical Physics
>> Trieste, Italy
>>
>> --------
>>
>> I have become so addicted to vi that I try to exit OpenOffice by typing
>> :wq!
>>
>
--
Dr. Marcos Verissimo Alves
Post-Doctoral Fellow
Condensed Matter and Statistical Physics Sector
International Centre for Theoretical Physics
Trieste, Italy
--------
I have become so addicted to vi that I try to exit OpenOffice by typing :wq!
