[molpro-user] The smallest exponent that can be used to specify a basis function
knizia at theochem.uni-stuttgart.de
Sat May 11 22:26:30 BST 2013
yes, there seems to be a bug somewhere down in the seward integral path:
It works with exponent 0.501e-12, but blows up with 0.500e-12. If I find
some time I'll look up what exactly is happening.
As a temporary work around, it is possible to use the argos integral
program instead (see attachment). With this an exponent of 1e-30 works
just fine if turning down the thresholds.
Thanks again for pointing out this trick for emulating IP/EA-EOM-CCSD. I
didn't know this one.
On Sat, 2013-05-11 at 19:59 +0200, Tatiana Korona wrote:
> Dear Gerald,
> A gaussian with the exponent equal to 1.E-50 has been used by Stanton and Gauss
> to obtain IP-EOM-CC3 energies directly from an EE-EOM-CC3 program, see
> J.Chem.Phys.,111,8785,1999, and ref. 18 there. If it were excluded by the
> program, then they wouldn't be able to calculate ionization potentials and make
> numbers for that paper. So, such a small exponent is certainly possible and
> _active_ in the program they used (probably Aces). I repeated this trick to
> obtain IP and EA with Molpro, but could use only the exponents like 1.E-12 for a
> continuum orbital. However, one can verify that this exponent is enough to
> provide a sufficient number of accurate digits for ionization potentials and
> electron attachments, e.g. I reproduced all digits given in papers on EA-EOM-CC
> You can test the following simple input
> ***, IP-EOM-CCSD (simulated with EE-EOM-CCSD)
> O,H1,R, !Z-matrix for water
> Theta=104 !start bond angle
> R=0.96 Ang !start bond distance
> eom,-5.1,vir_orb=6.1 ! fix on excitations TO this orbital
> This input will produce first 4 IPs for water. 6.1 is our zero-energy continuum
> orbital. However, if you change an additional exponent on oxygen from 1.e-12 to
> e.g. 1.e-15 or smaller, than you will get:
> ITERATION DDIFF GRAD ENERGY 2-EL.EN.
> DIPOLE MOMENTS DIIS ORB.
> 1 0.000D+00 0.000D+00 32025.50226135 64244.652599 NaN
> NaN NaN 0 start
> 2 0.000D+00 0.232D+02 -16.95078177 84.371664 NaN
> NaN NaN 1 diag
> 3 0.187D+02 0.165D+00 32657.17607612 65469.453071 NaN
> NaN NaN 2 diag
> 4 0.209D+02 0.106D+02 32655.12447108 65465.460273 NaN
> NaN NaN 3 diag
> 5 0.433D-01 0.108D+02 32649.67192410 65454.845120 NaN
> NaN NaN 4 diag
> ?TOTAL ENERGY UNREASONABLE, ETOT = 0.32650D+05, ENEST =
> in Hartree-Fock.
> Best wishes,
> On Sat, 11 May 2013, Gerald Knizia wrote:
> > On Wed, 2013-05-08 at 11:41 +0200, Evgeniy Gromov wrote:
> >> Gamess-US can converge SCF "hands down" with an exponent 1.E-50 .
> >> Molpro however could do the same with 1.E-10. 1.E-15 or smaller
> >> didn't work :(
> > Unlike other programs, Molpro never throws away basis functions if they
> > become unreasonable. Are you sure that your 1e-50 exponent basis
> > function actually ended up the calculation? Because for such a function
> > even handling its normalization coefficient would be a serious problem.
> > While it is perfectly possible to calculate integrals over such
> > functions (it is even done routinely with zero exponent functions for
> > implementing simpler integrals in terms of more complicated integrals),
> > using them as basis functions is very much not recommended. If you want
> > to try it anyway, be sure to turn off all integral screening,
> > compression, and approximation options.
> >  See JCTC 7 2387 (2011)
> > --
> > Gerald Knizia
> > _______________________________________________
> > Molpro-user mailing list
> > Molpro-user at molpro.net
> > http://www.molpro.net/mailman/listinfo/molpro-user
> 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
> `The man who makes no mistakes does not usually make anything.'
> Edward John Phelps (1822-1900)
-------------- next part --------------
***, IP-EOM-CCSD (simulated with EE-EOM-CCSD)
! original from Tatiana Korona, Sat May 11, 2013
! s,O,0.501e-12 ! works with seward
s,O,0.500e-30 ! doesn't work with seward, but does with argos.
O,H1,R, !Z-matrix for water
Theta=104 !start bond angle
R=0.96 Ang !start bond distance
! ^- explicitly call argos integral program, as a work-around. Seward apparently
! does something funky. It works just fine with an exponent of 0.501e-12, but
! doesn't with 0.500e-12. Should probably look up what exactly that is...
! - Gerald Knizia
eom,-5.1,vir_orb=6.1 ! fix on excitations TO this orbital
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