| 1:53:52 PM PDT - Wed, Apr 1st 2020 |
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Hi,
For Range separated functional wPBEh:
As $r_{12} => 0$, the HF exchange fraction is $\alpha$ i.e., cam_alpha, while the DFT exchange fraction is $(1-\alpha)$ i.e., cam_beta. As $r_{12} => \infinity$, the HF exchange fraction approaches $\alpha$ + $\beta$ i.e., hfexch 1.0 and the DFT exchange fraction approaches $(1- \alpha - \beta)$ i.e., xwpbe=0.8. It is not very clear to me how the scale factor is used.
I am interested in summing up $\alpha+\beta = 0.5$. I know that I can set hfexch as 0.5. But, how do I set my xwpbe value so that it is equal to $(1-0.5)$.
I would be happy if someone could help me to understand how the xwpbe value is set?
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