About lifetime

[lesheng]

Hi all,

I am now trying to calculate the QP lifetime of a system, and I noticed that there is a keyword "LifeTrCG" in the input file. My question is how can I interpret this variable, and will this value affect the calculation time significantly?

Thanks for your attention,

Lesheng Li

[Davide Sangalli]

Dear Lesheng Li,
the varable controls how the poles of the response function are described.

To compute the lifetimes yambo performes a GW calculation solving the frequency integral on the real axis. The response function enters in the integral.
By default poles are grouped together only if they are exactly degenerate in energy: LifeTrCG=100. (%)

If you reduce the value of the variable the poles will be grouped also if they are not exacty degenerate. In practice the variables ccontrols how much the code is sensitive to the energy dfference between two poles. 100% is the maximun sensitivity the code has. Reducing it, you could speed up your calculation but you should not to reduce it too much ...

Best,
Davide

[lesheng]

Dear Lesheng Li,
the varable controls how the poles of the response function are described.

To compute the lifetimes yambo performes a GW calculation solving the frequency integral on the real axis. The response function enters in the integral.
By default poles are grouped together only if they are exactly degenerate in energy: LifeTrCG=100. (%)

If you reduce the value of the variable the poles will be grouped also if they are not exacty degenerate. In practice the variables ccontrols how much the code is sensitive to the energy dfference between two poles. 100% is the maximun sensitivity the code has. Reducing it, you could speed up your calculation but you should not to reduce it too much ...

Best,
Davide

Hi Davide,

Thanks for your reply. I know this is a silly question, but how should I know which point will be the best one... I mean in the tutorial it uses 30, is there any specific reason to set this value as 30?

Plus, I was trying to calculate it with 30, but it shows me an error as following:

<03s> [01] Files & I/O Directories
<04s> [02] CORE Variables Setup
<04s> [02.01] Unit cells
<08s> [02.02] Symmetries
<08s> [02.03] RL shells
<08s> [02.04] K-grid lattice
<08s> [02.05] Energies [ev] & Occupations
<08s> [03] Transferred momenta grid
<08s> [03.01] G0W0 on the real axis
<08s> [03.02] Lifetimes Transitions Selector
<08s> [Life-CG] R(p) Tot o/o(of R) : 16368 317515 29
<08s> [03.03] Dynamical Dielectric Matrix
[ERROR] STOP signal received while in :[03.03] Dynamical Dielectric Matrix
[ERROR]Mem All. failed. Element X require 9.00073 [Gb]

Do you have any suggestion on this?

Thanks,
Lesheng Li