Yambo Community Forum

Hi, all;
I know how to calculate absorption spectrum using BSE. However, the energy region is limited by number of band. If I want to calculate photoemission spectrum (ionization potential is 50 eV) I have to include many bands. From numerical point of view it is difficult. Can I calculate the absorption spectrum for energy range 50-70 eV without need to include empty band representing the 10-50 eV?


Zhifan Chen
Clark Atlanta University
Atlanta GA 30314
USA

Dear Zhifan,
the BSE equation describe an absorption process, where electrons and holes are in the system
and they do interact each other. In photoemission, electrons are expelled from the system,
and the final state is an outgoing (free) electron. I would say the that BSE is not the right theory
to describe photoemission experiment. If you are interested in the band structures that can be measured
by photoemission experiment, than you can approach the problem in GW approximation. If you are
interested in the kinetic energy of the outgoing electron, to simulate a photoemission experiment
I think you have to move to other framework.

Best,

Daniele

Dear Daniele:
Thank you. Even calculation which can give some peak positions of the photoemission is fine. I am interested in the Ce@C82 photoemission. Since only one k point used in the calculation. No band structrue problem. Can GW calculation show the peak locations?


Zhifan Chen
Clark Atlanta University
USA