Re: [Wien] (no subject)

[pieper]

Dear Sikander Azam,

there seems to be agreement that DFT calculates the ground state, and 
that this state is occupied at T=0 K. So there are two cases:


1) If comparison with your experiment works at some finite temperature 
it stands to reason that the probability of observing the ground state 
is large. Thermodynamics tells you that this should be the case when 
excitation energies (at least for operators related to your experiment) 
are large compared to thermal energy.


2) If comparison with your experiment does not work ... you might look 
in this mailing list if you did something wrong in the calculations. Or 
your computational model of the situation is wrong. Or your system is 
not in the ground state. Or ...


Best luck with your coparisons

Martin Pieper

---
Dr. Martin Pieper
Karl-Franzens University
Institute of Physics
Universitätsplatz 5
A-8010 Graz
Austria
Tel.: +43-(0)316-380-8564


Am 09.06.2015 12:02, schrieb sikandar azam:

Dear All
Please answer me this question
explain why zero kelvin DFT based calculations are compared with
experimentally calculated values at >0 K temp"

with regards
sikander
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[Wien] Need your help please

[sikander Azam]

Dear all
I need the answer for the following question
I am using the Wien2k code to calculate the imaginary part of the complex
dielectric function   has certain limitations: the local field effects are
neglected, phonon contributions to the optical spectra band gap and
excitonic effects are not taken into account. But how i can comment the
accuracy (reasonability) of the obtained optical spectra.
with best regards
sikander
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