The spin-orbit DFT module (SODFT) in the NWChem code allows for the variational treatment of the one-electron spin-orbit operator within the DFT framework. The implementation requires the definition of an effective core potential (ECP) and a matching spin-orbit potential (SO). The current implementation does NOT use symmetry.
The actual SODFT calculation will be performed when the input module
encounters the TASK
directive (Section 5.10).
TASK SODFT
Input parameters are the same as for the DFT, see section 11 for specifications.
Some of the DFT options are not available in the SODFT. These are max_ovl
and
sic
.
Besides using the standard ECP and basis sets, see Section 8 for details, one also has to specify a spin-orbit (SO) potential. The input specification for the SO potential can be found in section 8.2. At this time we have not included any spin-orbit potentials in the basis set library.
Note: One should use a combination of ECP and SO potentials that were designed for the same size core, i.e. don't use a small core ECP potential with a large core SO potential (it will produce erroneous results).
The following is an example of a calculation of :
start uo2_sodft echo Memory 32 mw charge 2 geometry noautoz noautosym units angstrom U 0.00000 0.00000 0.00000 O 0.00000 0.00000 1.68000 O 0.00000 0.00000 -1.68000 end basis "ao basis" cartesian print U S 12.12525300 0.02192100 7.16154500 -0.22516000 4.77483600 0.56029900 2.01169300 -1.07120900 U S 0.58685200 1.00000000 U S 0.27911500 1.00000000 U S 0.06337200 1.00000000 U S 0.02561100 1.00000000 U P 17.25477000 0.00139800 7.73535600 -0.03334600 5.15587800 0.11057800 2.24167000 -0.31726800 U P 0.58185800 1.00000000 U P 0.26790800 1.00000000 U P 0.08344200 1.00000000 U P 0.03213000 1.00000000 U D 4.84107000 0.00573100 2.16016200 -0.05723600 0.57563000 0.23882800 U D 0.27813600 1.00000000 U D 0.12487900 1.00000000 U D 0.05154800 1.00000000 U F 2.43644100 0.35501100 1.14468200 0.40084600 0.52969300 0.30467900 U F 0.24059600 1.00000000 U F 0.10186700 1.00000000 O S 47.10551800 -0.01440800 5.91134600 0.12956800 0.97648300 -0.56311800 O S 0.29607000 1.00000000 O P 16.69221900 0.04485600 3.90070200 0.22261300 1.07825300 0.50018800 O P 0.28418900 1.00000000 O P 0.07020000 1.00000000 END ECP U nelec 78 U s 2 4.06365300 112.92010300 2 1.88399500 15.64750000 2 0.88656700 -3.68997100 U p 2 3.98618100 118.75801600 2 2.00016000 15.07722800 2 0.96084100 0.55672000 U d 2 4.14797200 60.85589200 2 2.23456300 29.28004700 2 0.91369500 4.99802900 U f 2 3.99893800 49.92403500 2 1.99884000 -24.67404200 2 0.99564100 1.38948000 O nelec 2 O s 2 10.44567000 50.77106900 O p 2 18.04517400 -4.90355100 O d 2 8.16479800 -3.31212400 END SO U p 2 3.986181 1.816350 2 2.000160 11.543940 2 0.960841 0.794644 U d 2 4.147972 0.353683 2 2.234563 3.499282 2 0.913695 0.514635 U f 2 3.998938 4.744214 2 1.998840 -5.211731 2 0.995641 1.867860 END dft mult 1 xc hfexch odft grid fine convergence energy 1.000000E-06 convergence density 1.000000E-05 convergence gradient 1E-05 iterations 100 mulliken end task sodft