[Pw_forum] Something strange in the calculation with the spin=2 and multiplicity=1

[vega lew]

Dear sir,

Do the both calculation output the singlet state energy?
If I want to compare the energy difference of singlet and triplet, which 
calculated singlet state energy should be used?

thank you for your help.

best wishes,

vega

On 1/13/2010 14:43, Paolo Giannozzi wrote:
> On Jan 13, 2010, at 6:41 , vega lew wrote:
>
>    
>> I have compare the results of two calculation for singlet state
>> with or without the option 'spin=2, multiplicity=1'.
>>      
> they aren't the same. A non-polarized calculation will yield S^2=0,
> Sz=0.
> A spin-polarized calculation with "multiplicity=1" will yield Sz=0
> but not
> necessarily S^2=0. See for instance J. Phys. Chem. B 105, 11227
> (2001) for a nice description of how neglecting to appreciate such
> difference may lead to unphysical results.
>
> P.
> ---
> Paolo Giannozzi, Dept of Physics, University of Udine
> via delle Scienze 208, 33100 Udine, Italy
> Phone +39-0432-558216, fax +39-0432-558222
>
>
>
> _______________________________________________
> Pw_forum mailing list
> Pw_forum at pwscf.org
> http://www.democritos.it/mailman/listinfo/pw_forum
>    
-- 

==================================================================================
Vega Lew ( weijia liu)
Graduate students
State Key Laboratory of Materials-oriented 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
***********************************************************************************************

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.quantum-espresso.org/pipermail/users/attachments/20100113/37edcd45/attachment.html>