Cubic response by mp2

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kaushikhatua
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Cubic response by mp2

Post by kaushikhatua » 26 Apr 2014, 02:25

Can anybody suggest input hints for cubic response calculation by mp2 method. I have done some cubic response run in hf and different dft functional and ccsd as well. Any help will be appreciated.

janus
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Re: Cubic response by mp2

Post by janus » 26 Apr 2014, 07:28

I would not go down that way as the MP2 response function does not have a pole structure that is consistent with the one of the exact linear response function, as pointed out in Ref. [1]. This paper also suggests to use the CC2 model instead if you're after an 'second-order' model. This model - unlike MP2 - gives response functions with a pole structure consistent with exact theory. You could also consider SOPPA, but here you'll only be able to go to linear response, not cubic.

Cheers,
Janus

Ref. [1]: Christiansen, Jørgensen, and Hättig, IJQC, 68, 1-52 (1998)

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