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Topic: Gaussian - Using Hybrid Functionals  (Read 1770 times)

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Offline mycotheologist

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Gaussian - Using Hybrid Functionals
« on: October 05, 2012, 06:57:52 PM »
I read that B3LYP is a hybrid functional which uses some HF method and some DFT method for its calculations. According to this page:
my professor told me that you can set the proportions of each method that the B3LYP uses yourself, so for example you can make it so it uses 70% HF and 30% DFT or 20% HF and 80% DFT etc. I'm trying to figure out how to do that. More specifically, I want to alter the proportion of the HF and slater functionals that B3LYP uses. According to this page: www.gaussian.com/g_tech/g_ur/k_dft.htm
the route section for the B3LYP method is as follows:
#P BLYP IOp(3/76=1000002000) IOp(3/77=0720008000) IOp(3/78=0810010000)
I'm confused about what these 3 terms represent. If I wanted to increase the amount of HF that B3LYP uses, what would I change in that route section? In the Gaussian manual, they say that Gaussian can use any model of the form:
P2EXHF + P1(P4EXSlater + P3ΔExnon-local) + P6EClocal + P5ΔECnon-local
heres a screenshot of this section of the manual:

Anyone know how I can alter the amount of HF used by B3LYP by altering that route section?

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