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qcscine / sparrow

https://scine.ethz.ch
BSD 3-Clause "New" or "Revised" License
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How to calculate S2 state ? #27

Open Yotta-private opened 2 months ago

Yotta-private commented 2 months ago

Hi,

I want to calculate the S2 state of a molucule, but I don't understand the meanning of the parameter provided by flag (-r and -n)

such as the command: sparrow -x example.xyz -c 0 -s 1 -M dftb3 -E -G -r 1 -o

if i set the r equal to 1, if it represents the root=1, that is, the S1 state?

and how to obtain multiple structures target a specific state (S1/S2/S3 etc ...) at the same time?

besides, what is the purpose of the reference state, mentioned in your python API example script!

Thanks!

weymutht commented 2 months ago

With the option -r you specify how many excited states should be computer by Sparrow. The option -n determines the initial dimension of the excited states subspace, i.e., the initial number of guess vectors to be used.

So, when you specify -r 1 you will only get the first (lowest) excitation energy. When you specify -r 10, you will get ten excitations.

The reference calculator is used to carry out a ground-state calculation. The resulting integrals are needed to calculate the excited state.

Yotta-private commented 2 months ago

ok，i have understood, thanks for your reply.