[molpro-user] E2exdisp in CCSD-SAPT converges to the wrong value in DC+BS
tania at tiger.chem.uw.edu.pl
Thu Sep 22 16:49:26 CEST 2016
my result for your no-df input with one line modification gives:
You have not set your artificial beryllium atom to dummy before the first part
of the calculation, therefore a wrong Enuc has been found for the dimer.
This was the main problem present in both inputs.
Additionally, for the DF case you should provide a more sensible auxiliary
basis set on dummy. Note that an auxiliary basis should describe PRODUCTS of
the atomic basis.
On Thu, 22 Sep 2016, Leonid Shirkov wrote:
> Hello Molpro Community,
> I was running some test jobs to calculate E2disp and E2exdisp energies
> for He2 with
> CCSD-SAPT at R=3.0 bohrs (interatomic distance). In order to speed
> up the convergence
> I employed midbond functions, and that works well for E2disp. However,
> E2exdisp converges
> to a smaller wrong value if DC+BS is used. Without the midbond
> functions, i.e. with DCBS,
> it converges to a value that agrees well with the previously
> reported CCSD-SAPT calculations,
> see 10.1063/1.2889006 and 10.1021/ct900232j.
> These values are Edisp=2.937 and E2exdisp=0.479 (mhartree units).
> Here is the outline of the results, '+' denotes the midbond functions,
> without density-fitting:
> Edisp Eexdisp
> avtz -2.599 0.391
> avdz+ -2.884 0.165
> avtz+ -2.907 0.235
> avqz+ -2.940 0.261
> with density-fitting (avXz/mp2fit used as the auxilary basis set):
> Edisp Eexdisp
> avtz -2.600 0.383
> avqz -2.853 0.454
> avdz+ -2.894 0.087
> avtz+ -2.910 0.103
> avqz+ -2.937 0.115
> I am attaching the inputs that I used for DC+BS calculations, both df
> and non-df versions.
> Is there anything wrong with my inputs? Perhaps some input parameters
> or thresholds ought
> to be tweaked? Increasing the integration grid by the 'dispgg' parameter to
> 20 does not help. Just in case it matters, I am using the 2012.1 version.
> I would appreciate any help and insight.
Dr. Tatiana Korona http://tiger.chem.uw.edu.pl/staff/tania/index.html
Quantum Chemistry Laboratory, University of Warsaw, Pasteura 1, PL-02-093 Warsaw, POLAND
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