Good day everyone,
I have a structure and one of the atom is AU. I need to optimize this structure in Gaussian. Which basis set, level of theory and memory would be suitable to run this DFT calculation?
Thank you in advance.
Dear Rinaa,
I think this post might be helpful --> https://www.researchgate.net/post/Which_basis_set_should_I_use_for_Cysteine_metal_complexes_in_Gaussian
https://www.basissetexchange.org
Check this website and select the element you are interested in, it will provide you with a list of basis sets that have been used for this element. For the memory it may be useful to choose a basis set from the list that has the least amount of functionals and try to use a memory size of 25-60 GB and see how far the calculation comes along during the optimization if the calculation does not complete then you know you most likely need to extend your memory or time duration depending on the node you are using to run the calculation. From the website it seems cc-pVDZ-pp has the least amount of functionals compared to the other basis sets. Though depending on your work you may want to use a augmented basis set. After you use the basis set that is at a lower level of theory then you can determine what memory may be suitable for a higher level basis set as in pVTZ/pVQZ/aug-cc-pVTZ...exc .
In a paper J. Phys. Chem.A, we used the quasirelativistic pseudopotential and basis set LANL2TZ with extra f-polarization functions for Au, which is able to reproduce the properties (in combination with the PBE functional) of gold, gold dimer, and Au20 cluster. The cost in memory is negligible if one gold atom is involved.
Article Binding of Trivalent Arsenic Onto the Tetrahedral Au20 and A...
The input section for the basis set and ECP can be obtained at the EMSL basis set library.
!---------------------------------------------------------------------- ! Basis Set Exchange ! Version v0.8.8 ! https://www.basissetexchange.org !---------------------------------------------------------------------- ! Basis set: LANL2TZ(f) ! Description: LANL2TZ(f) ! Role: orbital ! Version: 0 (Values from the Original Basis Set Exchange) !---------------------------------------------------------------------- Au 0 S 1 1.00 2.8090000 1.0000000 S 1 1.00 1.5950000 1.0000000 S 1 1.00 0.5327000 1.0000000 S 1 1.00 0.2826000 1.0000000 S 1 1.00 0.0598000 1.0000000 P 1 1.00 3.6840000 1.0000000 P 1 1.00 1.6660000 1.0000000 P 1 1.00 0.5989000 1.0000000 P 1 1.00 0.0977000 1.0000000 P 1 1.00 0.0279000 1.0000000 D 1 1.00 1.2870000 1.0000000 D 1 1.00 0.4335000 1.0000000 D 1 1.00 0.1396000 1.0000000 F 1 1.00 1.0500000 1.0000000 **** AU 0 AU-ECP 4 60 g potential 5 1 622.6287956 -60.0000000 2 136.2843607 -555.5292312 2 33.1549781 -168.0019785 2 9.9894895 -63.0399875 2 3.0481312 -4.2516681 s-g potential 6 0 194.7374304 3.0000000 1 351.5327447 38.6020880 2 122.3270402 864.8370727 2 32.0914617 374.9935520 2 5.2451812 289.7910100 2 4.4916223 -152.4532773 p-g potential 4 0 420.6158801 2.0000000 1 109.4417815 73.8885625 2 34.1714280 326.6729872 2 5.9879750 126.5814591 d-g potential 5 0 219.2666158 3.0000000 1 122.7297786 55.6793149 2 63.1063369 449.1987335 2 18.3684520 215.0269091 2 4.4972844 64.0840995 f-g potential 5 0 108.5506037 4.0000000 1 56.4795527 51.8065335 2 29.2069159 231.2183113 2 9.5440543 119.0047386 2 2.8965118 15.3424188
Rinaa Ramesh From my (limited) experience, you may utilize PBE1PBE/Def2TZVP level of theory and assign to your calculation an 18GB of memory. I'm also working on Au based complexes and this level of theory works the wonders for me. All the best!
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