[molpro-user] water monomer excitation energy

[Peterson, Kirk]

Dear Martin,

I agree you definitely want “aug” (although they are actually not quite diffuse enough to cover Rydberg states).  If you really want to correlate all the electrons you should use either aug-cc-pCVnZ or aug-cc-pwCVnZ. These include extra (tight) functions for correlating core electrons.  For excited states though, I doubt that core correlation is going to do much for you (relatively to the cost). If you’re interested in Rydberg states you should add some additional diffuse s and p functions.  Perhaps something like the following for valence QZ:

basis={
default,avqz
spdfg,O,avqz;c;
sp,O,even,1
}

best,

-Kirk

On Dec 21, 2014, at 1:50 PM, Martin Spenke <martinspenke at yahoo.de<mailto:martinspenke at yahoo.de>> wrote:

Dear Kirk,

Thanks a lot, i get now 7.6 eV, too.
I am not a basis set expert, but according to my boss, aug-basis sets are the best ones right now as they cover Rydberg states, too.
Which basis sets should one preferably take into account when correlating all the electrons
for specially investigation of dissociation behavior of molecules ?

Bests
Martin


"Peterson, Kirk" <kipeters at wsu.edu<mailto:kipeters at wsu.edu>> schrieb am 22:36 Sonntag, 21.Dezember 2014:


Dear Martin,

by default, Molpro puts this molecule in the xy plane.  If you turn on orbital printing, you’ll notice that it is symmetry 3 that contains the out-of-plane pz basis functions, not symmetry 2.  Spectroscopists will refer to that former symmetry at B1 even though Molpro happens to label it as B2.  Changing your input to symmetry 3 gives you an excitation energy around 7.6 eV.

It’s good to try to reproduce other people’s work as long as you don’t propagate their mistakes as well…..

best,

-Kirk


On Dec 21, 2014, at 1:16 PM, Martin Spenke <martinspenke at yahoo.de<mailto:martinspenke at yahoo.de>> wrote:

Dear Kirk,

Unfortunately i need the first excitation energy with B1 symmetry which is 7.5 eV.
Other state energies with different irreps are well reproduced but the B1 !
"One has to note which corresponds to out-of-plane symmetry in order to match convention"
How can i do this in the input file ? Is there any specific keyword for that ?

Aug-cc basis set is used here to be able to compare the results with those of Chipman results  J. Chem. Phys. 132, 244307 (2010)

Bests
Martin


"Peterson, Kirk" <kipeters at wsu.edu<mailto:kipeters at wsu.edu>> schrieb am 20:48 Sonntag, 21.Dezember 2014:


Dear Martin,

try sym=3 rather than sym=2 (B1 and B2 labels can be a bit tricky. One has to note which corresponds to out-of-plane symmetry in order to match convention)

Also, somewhat unrelated, but it is not good practice at all to correlate all the electrons with just a valence basis set as you do here.

best,

-Kirk


On Dec 20, 2014, at 4:09 AM, Martin Spenke <martinspenke at yahoo.de<mailto:martinspenke at yahoo.de>> wrote:

Dear all,

I try to calculate the first excitation energy of water monomer which is nearly 7.5 eV by mrci method,
but from what ever reason i get a very wrong result. I also tested different active spaces but no chance !

memory,80,m
gthresh,energy=1.d-08

angstrom
geomtyp=xyz
geometry={
O   0.000 0.000 0.0
H   0.757 0.586 0.0
H  -0.757 0.586 0.0
}
basis=aug-cc-pVQZ
!---------------------------------------
{hf;wf,10,1;}
!---------------------------------------
{multi;occ,6,2,2,0;closed,0;frozen,0;wf,10,sym=2;state,1}
!---------------------------------------
{mrci;occ,6,2,2,0;closed,0;core,0;wf,10,sym=2;state,1}
!---------------------------------------

Any idea why this is the case ?

Bests
Martin

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