about "states"

[xixi]

Dear developers,
what's the meaning of the two "1" in

States= "1 - 1"


if I want to plot the 11th states in o.exc_E_sorted file,
I use "11-1" or "1-11"?

Thanks !

Xi

Nanyang Technological University
Singapore

[andrea marini]

Dear developers,
what's the meaning of the two "1" in

States= "1 - 1"


if I want to plot the 11th states in o.exc_E_sorted file,
I use "11-1" or "1-11"?

The variable States follows the syntax " 1st_state - last_state" with the index referring to the energy ordered states (as written in o.exc_E_sorted). So to plot the 11th state you need to set States= " 11 - 11 " . Be careful to leave spaces otherwise the parser will get confused.

Please also note that ypp will add to the state you asked for all other states that will be energy degenerate. This in order to respect spatial symmetries.

[xixi]

Dear andrea;

thanks for your reply,
but how can I identify the transition energy of E11, E12 in the o.exc_E_sorted file?
I didn't understand the meaning of the "1,2,3" ordered in the o.exc_E_sorted file.

Thanks!


Xi Zhu
School of Materials Science And Engineering,
Nanyang Technological University,
Blk N4.1, Nanyang Avenue,
Singapore 639798

[Daniele Varsano]

Dear Xi Zhu,
could you be more explicit? What do you want to calculate/visualze?
In the o.exc_E_sorted you have the excitation energies sorted in energy with this structure:
# E [ev] Strength Index
#
6.495275 0.389558 1.000000
6.500834 0.102615 2.000000
6.505801 1.000000 3.000000
7.390 0.3106E-6 4.000

First column: Excitation energy
Second column : Oscillator strength
Third Column: Index

If you look the file sorted by intensity the index it is not monotone.

This is the index you should consider in the input file for plotting
an excitonic wave function referred to excitation you are interested in..

If you want to look at the KS transition that the more participate on each excitation consider
the ypp -e a option,
indicate the index of the excitation you want to look at (in you case 11 or 12 ) and you will have this information in the o.exc_weights_ file.

But I'm not sure on what you are meaning for E11 , E12
Hope it helps,

Daniele

[xixi]

Dear Varsano;
my problem is
I want to get the transition energy between valence band 1 (v1)and conduction band 1 (c1) ,
but I can't get this information from ypp,
Thanks!

Xi zhu

School of Materials Science And Engineering,
Nanyang Technological University,
Blk N4.1, Nanyang Avenue,
Singapore 63979

[Daniele Varsano]

Dear Xi Zhu,

when you solve the Bethe-Salpeter equation you are not in a single-particle picture!!
The excitation energy you get comes from the diagonalization of an excitonic Hamiltonian
that is written in the valence-conduction wave function basis.
The wave function corresponding to the excitation can be written as a
\sum_ij A_ij phi_i phi_j, where i runs over occupied states and j over unoccupied states, so
you can look at the weight of each single-particle transition that "participate" in the
excitation energy (as I told you in the last post).

I want to get the transition energy between valence band 1 (v1)and conduction band 1 (c1)

If you want to look at the single-particle transition energy, you don't need ypp, and neither yambo,
you can look at the differences between the KS eigenvalues that comes from your DFT calculation.
This information is also reported in the BS spectrum file in the last columns, you will find
peaks in correspondence of the single-particle energy differences with the height that correspond
to their oscillator strength.

I hope this helps to clarify.

Cheers,

Daniele