Dear Daniele,

Thank you very much for your help, but I still have some questions about computing triplet excitations.

In the post (

viewtopic.php?f=28&t=1385&p=6604&hilit=triplet#p6604), your answers to the singlet-triplet splitting calculations are as follows

Please note that singlet triplet splitting can be calculated by calculating separately singlet and triplet excitations.

Triplet excitations are calculated by omitting the exchange term in the excitonic Hamiltonian. See e.g. Rohlfing and Louie PRB 62, 4927 (2000).

It is also possible to consider non collinear spin, by calculating a ground state including spin orbs coupling and the BSE will be solved in a spinorial space.

I don't quite understand the meaning of the last sentence. Does it mean that if the ground state calculation contains SOC, the yambo calculation can directly produce the triplet excitation eigen-energies?

I will be very grateful that if you can give me a final confirmation.

Best,

Chenhai Shen