[Pw_forum] How to plot molecular hybrid orbitals for surface slab geometry?

[vega lew]

Dear sir,

>>was this person by any chance an organic chemist??

to some extent.

>>this is what the gods of quantum chemistry created the population
>>analysis for. after you project on atomic (pseudo) wavefunctions you
>>can determine the amount of s-,p-,d-character of your individual states.
>>this is not without problems, though. the partitioning is somewhat
>>arbitrary and the projection from plane waves to atomic orbitals is
>>not complete, i.e. you are missing out on some contributions that do
>>not fit into the atomic orbital basis you provide.

Do you mean the projwfc.x could help me quite a lot? If so, i would be very
happy.
I just identify a kind of structural feature for certain atomic arrangement.
if the atom
near the surface arrange that way, dissociative adsorption of water could be
favourable.
But I can't tell why that rules is correct? so I tried to explain something
at electronic
scale. Do you think I could explain this just by plotting some DoS/pDoS for
certain atoms?
Is there a systemic tutorial or text book for it?

By the way, I'm considering intel Quadcore XEON 5500 series CPU and
corresponding dual socket motherboard.
the memory bandwith could be tripled as I7 series. May I have your opinion
about QE performance on 5500 series
servers? Do you think it is really a sensible decision to spend ~$20,000 for
four XEON 5500 servers.

thank you for your time

vega

On Sun, Apr 5, 2009 at 10:17 PM, Axel Kohlmeyer <akohlmey at cmm.chem.upenn.edu
> wrote:

> On Sun, 2009-04-05 at 19:06 +0800, vega lew wrote:
> > Dear all,
> >
> > I'm studying the water splitting behavior on certain surfaces. And I
> > have identified a special structural features of the surface for water
> > dissociation.
> > But I can't tell why that kind of feature did a positive effect on
> > water dissociation. One visitor to our group thought this behavior has
> > a strong dependence of molecular hybrid orbitals of atoms near the
>
> was this person by any chance an organic chemist??
>
> >  surface. From a Structural Chemistry viewpoint, certain atomic
> > structure could result in different hybrid styles of molecular
> > orbitals. The feature I identified may have a favorable shape of
> > hybrid orbitals for water approaching and dissociating.
>
> <climbing on soapbox>
>
> you have to forget about the nice orbital pictures that you see in
> chemistry text books. they are a visual crutch to break a problem
> where everything interacts with everything into individual additive
> components. it still works surprisingly well, but only after the fact,
> i.e. you can rationalize findings that you got elsewhere in a simplified
> form.
>
> </descending from soapbox>
>
> >
> > I wonder whether QE has a function for ploting the shape of hybrid
> > molecular orbitals near the surface.
>
> this is what the gods of quantum chemistry created the population
> analysis for. after you project on atomic (pseudo) wavefunctions you
> can determine the amount of s-,p-,d-character of your individual states.
> this is not without problems, though. the partitioning is somewhat
> arbitrary and the projection from plane waves to atomic orbitals is
> not complete, i.e. you are missing out on some contributions that do
> not fit into the atomic orbital basis you provide.
>
> cheers,
>   axel.
>
> >
> > thank you for reading
> >
> > best,
> >
> > vega
> >
> > --
> >
> ==================================================================================
> > Vega Lew ( weijia liu)
> > PH.D Candidate in Chemical Engineering
> > State Key Laboratory of Materials-oriented Chemical Engineering
> > College of Chemistry and Chemical Engineering
> > Nanjing University of Technology, 210009, Nanjing, Jiangsu, China
> >
> ******************************************************************************************************************
> > Email: vegalew at gmail.com
> > Office: Room A705, Technical Innovation Building, Xinmofan Road 5#,
> > Nanjing, Jiangsu, China
> >
> ******************************************************************************************************************
> > _______________________________________________
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>
> --
> =======================================================================
> Axel Kohlmeyer   akohlmey at cmm.chem.upenn.edu   http://www.cmm.upenn.edu
>   Center for Molecular Modeling   --   University of Pennsylvania
> Department of Chemistry, 231 S.34th Street, Philadelphia, PA 19104-6323
> tel: 1-215-898-1582,  fax: 1-215-573-6233,  office-tel: 1-215-898-5425
> =======================================================================
> If you make something idiot-proof, the universe creates a better idiot.
>
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>



-- 
==================================================================================
Vega Lew ( weijia liu)
PH.D Candidate in Chemical Engineering
State Key Laboratory of Materials-oriented Chemical Engineering
College of Chemistry and Chemical Engineering
Nanjing University of Technology, 210009, Nanjing, Jiangsu, China
******************************************************************************************************************
Email: vegalew at gmail.com
Office: Room A705, Technical Innovation Building, Xinmofan Road 5#, Nanjing,
Jiangsu, China
******************************************************************************************************************
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