QuantumATK Forum

QuantumATK => General Questions and Answers => Topic started by: ramkrishna on May 22, 2015, 20:11

Title: Joint density of states
Post by: ramkrishna on May 22, 2015, 20:11

Dear Sir,
In optical spectrum we can directly calculate the real and imaginary part of the dielectric. However, we know the imaginary part is determined by the joint density of states (joint DOS). Is it possible to calculate (or extract from the Im_epsilon) the joint DOS?

Thanks
Ramkrishna

Title: Re: Joint density of states
Post by: zh on May 25, 2015, 04:37

By using an approximated relationship between the JDOS  and the imaginary part of the dielectric (\epsilon_2):  $\epsilon \propto  \frac{JDOS} { \omega^2}$,
(see http://etsf.polytechnique.fr/sites/default/files/dft-II-silva.pdf)
you may obtain the JDOS.

Title: Re: Joint density of states
Post by: ams_nanolab on July 31, 2015, 11:11

This Eq. for the JDOS seems confusing. The absorption eps_2 contains info about dipole matrix elements (oscillator strength) while the JDOS does not, how can both be proportional?

Title: Re: Joint density of states
Post by: zh on August 3, 2015, 08:52

Please read the 22nd page of the Silvana Botti's presentation (http://etsf.polytechnique.fr/sites/default/files/dft-II-silva.pdf). There is an assumption that the optical matrix elements are assumed to constant.