A question about MP2 energy gradient

Clicked A Few Times	10:44:15 AM PST - Sat, Mar 3rd 2012 I want to ask if the code for MP2 energy gradient is available for orbitals from dft? If I want to run double hybrid dft for geometry optimization analytically, how can I use it? Thanks!

Forum Vet	3:14:57 PM PDT - Tue, Mar 13th 2012 dftmp2 semidirect Neil, You need to use the "dftmp2 semidirect" keyword in order to be able to run double hybrid geometry optimizations. Here is a simple example. Cheers, Edo start h2 geometry h 0 0 0 h 0 0 1 end basis * library 6-31g end dft xc HFexch 0.53 becke88 0.47 lyp 0.73 mp2 0.27 dftmp2 semidirect end task dft optimize

Gets Around	12:03:43 AM PDT - Fri, Jun 7th 2013 Has this been verified to be consistent with DHDF gradient implementations in other codes? I was very careful when I implemented DHDF to verify against numbers that Grimme gave me from Turbomole but only for ground-state energies. It would be good if someone could compare semidirect analytic gradients in NWChem for DHDF with the finite-difference gradient to be sure that they are identical.

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