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Re^2: Increasing weight of exact HF-exchange in functional (option HFX) in TDDFT calculations

GrEv
grevgen13@gmail.com


Dear Thom,

Thanks very much for your reply. Indeed, the BHHLYP functional has been used a lot in TDDFT calculations. Is seems to make the charge-transfer states higher in energy indeed. In fact, it makes overestimate of such states in energy quite much, at least in my case. On the other hand, if I increase the weight of HF-exchange in the B3LYP functional from 0.2 to 0.3 (using the HFX option in Firefly) I reproduce the results for the charge-transfer states obtained with an ab-initio (CC2) method. The question is/was if such a kind of modification of B3LYP is "allowed" and might have been used before?

Best regards,
Evgeniy


On Wed Aug 3 '16 9:28pm, Thomas Pijper wrote
--------------------------------------------
>Dear Evgeniy,

>This is indeed possible. The BH&HLYP functional (which uses 50 % exact exchange) is actually a commonly used functional for TDDFT calculations. References that use this functional should be plentiful.
>
>
>Kind regards,
>Thom
>
>
>
>On Wed Aug 3 '16 1:44pm, GrEv wrote
>-----------------------------------
>>Hello,

>>I wonder if one can use the option HFX, to increase the weight of exact HF-exchange in a hybrid functional (B3LYP), to "remedy" the problem with charge-transfer states in TDDFT calculations. I would appreciate very much a reference to some works where this was used.

>>Best regards,
>>Evgeniy


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