LDA energy calculation inconsistent with Gaussian

[Eric]

Dear prof,

I have test the energy calculation using LDA+6-311+G(2d,p) on H atom. Here is my input :

start H

 title "H in 6-311+G(2d,p) basis set " 

geometry units angstrom

 H      0.00000000    0.00000000    0.00000000

end

basis 

 * library 6-311+G(2d,p) 

end 

dft 

 MULT 2 

end 

task dft

The resulting Total DFT energy is -0.478009988254. I did the same test using Gaussian, which give me -0.496113573519. Is there anything wrong with my nw file?

Thanks in advance!

Best,

Eric

[Edoardo Aprà]

adding the following input line to the DFT section

xc slater vwn_1_rpa

gives you

Total DFT energy =       -0.496113571541

PS. The default LDA functionals in NWChem are slater vwn_5

https://nwchemgit.github.io/Density-Functional-Theory-for-Molecules.html#exchange-correlation-functionals

[Shuyang Ye]

Thank you for the response! Is slater vwn_1_rpa the most accurate LDA version?

Edoardo Aprà <edoard...@gmail.com> 于2021年6月29日周二 下午5:22写道：

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[Edoardo Aprà]

The following posting might serve as  a good reference on this topic

http://www.ccl.net/cgi-bin/ccl/message-new?1995+12+05+008

[Shuyang Ye]

Thank you! The posting is really helpful! 

Edoardo Aprà <edoard...@gmail.com> 于2021年6月29日周二 下午7:03写道：

To view this discussion on the web visit https://groups.google.com/d/msgid/nwchem-forum/c825e861-9fd3-44eb-8a0a-2dac433e3384n%40googlegroups.com.

[Eric]

Here is another case, O3. With NWChem, I got a total DFT energy of -224.179924522834. But, with Gaussian and the same functional+basis, I got -224.412012232. This difference caused trouble when I calculate the electron affinity of O3. 

[Edoardo Aprà]

The topic of the open-shell singlet has already been discussed a few times in the old forum.

The following thread as all the information you need to get the correct open-shell singlet state in NWChem

https://nwchemgit.github.io/Special_AWCforum/st/id305/How_to_get_the_open_shell_single....html