[molpro-user] Extrapolation to the complete basis set limit of def2-anzvp basis sets.
Peterson, Kirk
kipeters at wsu.edu
Wed Oct 23 16:25:38 BST 2013
Dear Alexander (Sasha),
the def2- basis sets to my knowledge were never designed explicitly for basis set extrapolation. They do provide a series of basis sets that range from small to large, but I am not aware of a study that uses them in CBS extrapolations. You might though want to consider the TZVPP and QZVPP sets since these have f and g functions, respectively, compared to TZVP and QZVP. In any event if you are using lmax-style extrapolations, you only need 2 basis sets to do this. Typically 3-point extrapolations that include a DZ-quality set is not recommended except for specialized extrapolation formulas.
best,
-Kirk
PS - also, you might want to take a look at the top of the file def2-nzvpp-orb.libmol in your molpro lib directory for some notes about def2- vs. dhf-
On Oct 23, 2013, at 5:17 AM, sasha medvedev <vinsanity305 at mail.ru<mailto:vinsanity305 at mail.ru>> wrote:
Dear molpro users.
We calculate ab initio potentials of alkali metal - inert gase weakly bound molecules.
Our research group uses def2-asvp,atzvp,aqzvp basis sets for extrapolation to a complete basis set limit (2 and 3 point formulae from molpro manual-Lx,LHx,Ex2) .
But we stress, that these basis sets are not suitable for a 3-point extrapolation at all, because the lmax is the same for asvp and atzvp basis sets for Rb and Cs atoms:
For Cs:
def2-asvp
Library entry Cs ECP ECP46MDF selected for group 1
Library entry CS S def2-SVP selected for orbital group 1
Even tempered Cs S diffuse selected for group 1 nprim= 1 centre= 0.005 ratio= 2.271 dratio= 1.000
Library entry CS P def2-SVP selected for orbital group 1
Even tempered Cs P diffuse selected for group 1 nprim= 1 centre= 0.003 ratio= 5.198 dratio= 1.000
Library entry CS D def2-SVP selected for orbital group 1
Even tempered Cs D diffuse selected for group 1 nprim= 1 centre= 0.008 ratio= 4.004 dratio= 1.000
def2-atzvp
Library entry Cs ECP ECP46MDF selected for group 1
Library entry CS S def2-TZVP selected for orbital group 1
Even tempered Cs S diffuse selected for group 1 nprim= 1 centre= 0.005 ratio= 2.271 dratio= 1.000
Library entry CS P def2-TZVP selected for orbital group 1
Even tempered Cs P diffuse selected for group 1 nprim= 1 centre= 0.003 ratio= 5.198 dratio= 1.000
Library entry CS D def2-TZVP selected for orbital group 1
Even tempered Cs D diffuse selected for group 1 nprim= 1 centre= 0.004 ratio= 3.904 dratio= 1.000
For Rb:
def2-asvp
Library entry Rb ECP ECP28MDF selected for group 2
Library entry RB S def2-SVP selected for orbital group 2
Even tempered Rb S diffuse selected for group 2 nprim= 1 centre= 0.006 ratio= 2.320 dratio= 1.000
Library entry RB P def2-SVP selected for orbital group 2
Even tempered Rb P diffuse selected for group 2 nprim= 1 centre= 0.003 ratio= 6.503 dratio= 1.000
Library entry RB D def2-SVP selected for orbital group 2
Even tempered Rb D diffuse selected for group 2 nprim= 1 centre= 0.003 ratio= 8.238 dratio= 1.000
def2-atzvp
Library entry Rb ECP ECP28MDF selected for group 1
Library entry RB S def2-TZVP selected for orbital group 1
Even tempered Rb S diffuse selected for group 1 nprim= 1 centre= 0.006 ratio= 2.287 dratio= 1.000
Library entry RB P def2-TZVP selected for orbital group 1
Even tempered Rb P diffuse selected for group 1 nprim= 1 centre= 0.006 ratio= 2.500 dratio= 1.000
Library entry RB D def2-TZVP selected for orbital group 1
Even tempered Rb D diffuse selected for group 1 nprim= 1 centre= 0.003 ratio= 3.569 dratio= 1.000
So, a 3-point extrapolation is forbidden here, because we need at least 3 basis sets with different lmax (unfortunately, we have only two: atzvp,aqzvp).
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Besides that, extrapolation formulae depend on the cardinal number n (which is the part of the basis set name - i.e. 2 for asvp, 3 for atzvp, 4 for aqzvp, and should be equal to the lmax). When we looked through output file, we noticed, that the same basis set has different lmax for different atoms:
For Cs (def2-aqzvp basis set with ecp46mdf)
Library entry Cs ECP ECP46MDF selected for group 2
Library entry AR S def2-QZVP selected for orbital group 1
Even tempered Ar S diffuse selected for group 1 nprim= 1 centre= 0.068 ratio= 2.441 dratio= 1.000
Library entry AR P def2-QZVP selected for orbital group 1
Even tempered Ar P diffuse selected for group 1 nprim= 1 centre= 0.044 ratio= 2.497 dratio= 1.000
Library entry AR D def2-QZVP selected for orbital group 1
Even tempered Ar D diffuse selected for group 1 nprim= 1 centre= 0.123 ratio= 2.407 dratio= 1.000
Library entry AR F def2-QZVP selected for orbital group 1
Even tempered Ar F diffuse selected for group 1 nprim= 1 centre= 0.223 ratio= 2.440 dratio= 1.000
Library entry AR G def2-QZVP selected for orbital group 1
Even tempered Ar G diffuse selected for group 1 nprim= 1 centre= 0.403 ratio= 2.500 dratio= 1.000
Library entry CS S def2-QZVP selected for orbital group 2
Even tempered Cs S diffuse selected for group 2 nprim= 1 centre= 0.008 ratio= 1.465 dratio= 1.000
Library entry CS P def2-QZVP selected for orbital group 2
Even tempered Cs P diffuse selected for group 2 nprim= 1 centre= 0.004 ratio= 2.468 dratio= 1.000
Library entry CS D def2-QZVP selected for orbital group 2
Even tempered Cs D diffuse selected for group 2 nprim= 1 centre= 0.004 ratio= 2.911 dratio= 1.000
Library entry CS F def2-QZVP selected for orbital group 2
Even tempered Cs F diffuse selected for group 2 nprim= 1 centre= 0.235 ratio= 2.500 dratio= 1.000
For Rb (def2-qzvp with ecp28mdf)
Library entry Rb ECP ECP28MDF selected for group 2
Library entry AR S def2-QZVP selected for orbital group 1
Even tempered Ar S diffuse selected for group 1 nprim= 1 centre= 0.068 ratio= 2.441 dratio= 1.000
Library entry AR P def2-QZVP selected for orbital group 1
Even tempered Ar P diffuse selected for group 1 nprim= 1 centre= 0.044 ratio= 2.497 dratio= 1.000
Library entry AR D def2-QZVP selected for orbital group 1
Even tempered Ar D diffuse selected for group 1 nprim= 1 centre= 0.123 ratio= 2.407 dratio= 1.000
Library entry AR F def2-QZVP selected for orbital group 1
Even tempered Ar F diffuse selected for group 1 nprim= 1 centre= 0.223 ratio= 2.440 dratio= 1.000
Library entry AR G def2-QZVP selected for orbital group 1
Even tempered Ar G diffuse selected for group 1 nprim= 1 centre= 0.403 ratio= 2.500 dratio= 1.000
Library entry RB S def2-QZVP selected for orbital group 2
Even tempered Rb S diffuse selected for group 2 nprim= 1 centre= 0.006 ratio= 2.064 dratio= 1.000
Library entry RB P def2-QZVP selected for orbital group 2
Even tempered Rb P diffuse selected for group 2 nprim= 1 centre= 0.005 ratio= 2.591 dratio= 1.000
Library entry RB D def2-QZVP selected for orbital group 2
Even tempered Rb D diffuse selected for group 2 nprim= 1 centre= 0.003 ratio= 2.877 dratio= 1.000
Library entry RB F def2-QZVP selected for orbital group 2
Even tempered Rb F diffuse selected for group 2 nprim= 1 centre= 0.341 ratio= 2.500 dratio= 1.000
So, def2-aqzvp basis set can change its cardinal number n, but it is still called aqzvp!
Does it mean, that we should use different n (i.e. cardinal numbers or lmax of a particular basis set) in the extrapolation formulae for the same basis set, if lmax changes?
So, it is impossible to extrapolate the energy of the system, which contains atoms with different lmax (when we use def2-anzvp
basis sets), because in such a case n is not determined (something like (n1+n2)/2 - which is not even an integer). Am I right?
I am also interested in scientific papers, in which extrapolation to the complete basis set limit of def2-asvp/atzvp/aqzvp basis sets is carried out (if extrapolation is allowed for def2-anzvp basis sets).
Alexander Medvedev,
student of the 5th course of
Lomonosov Moscow State University
Department of Chemistry
Chair of Laser Chemistry
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