Hi Manu, The last release of the code does not allow for k-point sampling, that's why you get an error message. You would need to use a supercell. If you have done a gamma only calculation for your system that's probably why you get a spectrum that does not match at all experiments. Additionally, the Bethe-Salpeter equation is considered the most accurate method for bulk solids. Best, Dario
On Thu, Jul 21, 2016 at 9:42 AM, Manu Hegde <[email protected]> wrote: > Hi Dario, > Thank you very much. I have done some calculations for UV-Vis (see > attached) and it is no where matching my experimental results in case of > bcc-In2O3. Is it due to pseudopotential (I have used PBE USPP)?. Also I am > unable to BZ sampling on k-mesh and TDDFT shown me an error. > > Regards, > Manu > (University of Waterloo) > > On Wed, Jul 20, 2016 at 8:09 PM, dario rocca <[email protected]> wrote: > >> Dear Manu, >> You can simply extract it with the command >> $ grep "S(E)" prefix.plot_chi.dat > file_for_plot >> and use your favorite program to plot it. >> Best, >> Dario >> >> On Wed, Jul 20, 2016 at 10:49 AM, Manu Hegde <[email protected]> wrote: >> >>> Hello Dario, >>> >>> I have done the similar calculations, it went well, after running >>> turbo_spectrum.x Do you have any code to extract S(E) or I have to do it >>> manually? >>> >>> Manu >>> (University of Waterloo) >>> >>> On Tue, Jul 19, 2016 at 8:24 PM, dario rocca <[email protected]> wrote: >>> >>>> Dear SungHwan, >>>> please refer to >>>> http://arxiv.org/pdf/1402.0486.pdf >>>> and >>>> >>>> http://urania.sissa.it/xmlui/bitstream/handle/1963/5797/turboTDDFT-CPC.pdf?sequence=1 >>>> for more details. >>>> >>>> In the output of the postprocessing chi_1_1 is the xx component of the >>>> dynamical polarizability, chi_1_2 the xy component, etc. >>>> Often chi is indicated as \alpha in the papers. >>>> Specifically you would have >>>> >>>> Component energy of the perturbation real part of >>>> chi imaginary >>>> (indicated either as E or \omega) >>>> chi_1_1= 0.000000000000000E+00 0.955769346791472E+01 >>>> 0.000000000000000E+00 >>>> ......... >>>> >>>> As you correctly say the absorption spectrum is related to the >>>> imaginary part of the average of chi multiplied by E (the energy E is often >>>> indicated as \omega). >>>> This averaged quantity is contained in S(E). Specifically S(E) is the >>>> strength function defined as >>>> S(E)=2m/(\pi*e^2*\hbar) * E*Im[chi(E)], where chi has been averaged >>>> over the 3 spatial directions. >>>> This definition is convenient because S(E) satisfies the f-sum rule. >>>> So if you extract S(E) and plot it you will have the absorption >>>> spectrum. >>>> Let me know if it's still not clear >>>> Best, >>>> Dario >>>> >>>> >>>> >>>> >>>> On Tue, Jul 19, 2016 at 4:01 PM, SungHwan Choi < >>>> [email protected]> wrote: >>>> >>>>> hi, I am a newbie for turboTDDFT. Now, I ran a simple example. It >>>>> was assume. Now I have prefix.plot_chi.dat file. then I don't know >>>>> how to generate absorption spectrum from that file and dielectric >>>>> constant values. As far as I understood, the absorption spectrum is >>>>> related to imaginary part of average \chi value. but in the file there >>>>> are 9 >>>>> values >>>>> chi_1_1 >>>>> chi_2_1 >>>>> chi_3_1 >>>>> chi_1_2 >>>>> chi_2_2 >>>>> chi_3_2 >>>>> chi_1_3 >>>>> chi_2_3 >>>>> chi_3_3 >>>>> This is 3*3*3 tensor. how do I get an absorption spectrum and >>>>> dieletric constant values? by the way S(E) means what? >>>>> >>>>> Sincerely >>>>> Sunghwan Choi >>>>> >>>>> _______________________________________________ >>>>> Pw_forum mailing list >>>>> [email protected] >>>>> http://pwscf.org/mailman/listinfo/pw_forum >>>>> >>>> >>>> >>>> _______________________________________________ >>>> Pw_forum mailing list >>>> [email protected] >>>> http://pwscf.org/mailman/listinfo/pw_forum >>>> >>> >>> >>> _______________________________________________ >>> Pw_forum mailing list >>> [email protected] >>> http://pwscf.org/mailman/listinfo/pw_forum >>> >> >> >> _______________________________________________ >> Pw_forum mailing list >> [email protected] >> http://pwscf.org/mailman/listinfo/pw_forum >> > > > _______________________________________________ > Pw_forum mailing list > [email protected] > http://pwscf.org/mailman/listinfo/pw_forum >
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