I am doing a optical absorption calculation using IP approximation. And I have some points for clarification.
1: Is IPA same as RPA? Or RPA includes more advances approximations as well?
2: I have read the following tutorial:
http://www.yambo-code.org/wiki/index.ph ... icle_level
Here it is written that "Non-local commutator" can play a huge difference in the computational time, so, I want to know how can I guess that is this term important for my system or not? Is the inclusion of this term makes the results more accurate? If I will have to calculate the spectra with both NL commutator and without it then there is no benefit, I mean, to make calculation without it. Since my system is large that's why I am worried about it.
3: Why we are going to q || (1 0 0) direction in the above-mentioned tutorial to not include the "Non-local commutator"? This is the direction of the applied electric field to the material. Isn't it?
4: In optics runlevel:
Code: Select all
% [b]QpntsRXd[/b] 1 | 1| # [Xd] Transferred momenta % ETStpsXd= [b]1001 [/b] # [Xd] Total Energy steps
5: My calculation is taking the enormous time, I am attaching the necessary files as attachement to have your feeedback to optimize things. I can reduce the number of G-vectors (which is the default now). What else can I do, I mean, NL commutator and only q=0 calculations?
LUMS - Pakistan