Hi Anne, and everybody, My question about the dynamical polarizability was more for the developers, because I don not find it clear in the documentation. Let me focus my question
The electronic dynamical polarizability is calculated with the turbo-TDDFPT code. Then, what dynamic polarizability is calculated with PHONON ? Knowing some of he applications of the PHONON code, I foresee two logical answers a) the polarizabilty due to phonon excitations, plus the electronic polarizabilty in the static limit, i.e., for energy much smaller than the electronic transition energies. b) the same, but with the frequency dependent electronic contributions, calculated with ground state DFT instead of TDDFT. and the answer is c) ...........? I do not believe that the frequencies in the example 33 are in Ry. They are too high if the units are Ry, and PHONON is esentially a code to calculate phonons and derived properties. I would bet for THz. best regards Eduardo DearEduardo You wanted to know What exactly this dynamical polarizability is? In fact, when a system (atomic, molecule,...) is submitted to an external field, its electrons are reorganised according to the frequence of that external field. One can then evaluate the aptitude of the system to be subject to that reorganisation by evaluating the polarizability. Particularly when the phenomenon is time dependent, one evaluate the dynamical polarizability. is it include the electronic , phonon or both contributions? For my case, I want to consider C60 as a dielectric sphere of finite or infinite thickness, I don't know exactly if the phonon contribution is relevant, but I am mostly evolved in electronic calculations. What are the frequency units (THz, eV? ) in the example 33. As I see in output of that example 33 (it is also the case for almost all the other input and output files of espresso-4.3.1), the energies and frequencies are in Ry Kind regard -- Eduardo Menendez Proupin Departamento de Qu?mica Fisica Aplicada Facultad de Ciencias Universidad Aut?noma de Madrid 28049 Madrid, Spain Phone: +34 91 497 6706 On leave from: Departamento de Fisica, Facultad de Ciencias, Universidad de Chile URL: http://fisica.ciencias.uchile.cl/~emenendez "*Padece, espera y trabaja para gentes que nunca conocer? y que a su vez padecer?n, esperar?n y trabajar?n para otros, que tampoco ser?n felices, pues el hombre ans?a siempre una felicidad situada m?s all? de la porci?n que le es otorgada. Pero la grandeza del hombre est? precisamente en querer mejorar lo que es. En imponerse Tareas. En el Reino de los Cielos no hay grandeza que conquistar, puesto que all? todo es jerarqu?a establecida, inc?gnita despejada, existir sin t?rmino, imposibilidad de sacrificio, reposo y deleite. Por ello, agobiado de penas y de Tareas, hermoso dentro de su miseria, capaz de amar en medio de las plagas, el hombre puede hallar su grandeza, su m?xima medida en el Reino de este Mundo*". Alejo Carpentier, El reino de este mundo, (1949). Translate from spanish here http://translate.google.com/?hl=&ie=UTF-8&text=&sl=es&tl=en -------------- next part -------------- An HTML attachment was scrubbed... URL: http://www.democritos.it/pipermail/pw_forum/attachments/20120124/b74d06a8/attachment.htm