projecting small basis onto larger one

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Anyone have any idea's on this?

Thanks Geoff.

  • Huub Forum:Admin, Forum:Mod, NWChemDeveloper, bureaucrat, sysop
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Hi Geoff,
As far as I can remember this should be automatic. If you run an SCF calculation and save the movecs with the "vectors output" directive (see http://www.nwchem-sw.org/index.php/Release62:Hartree-Fock_Theory_for_Molecules#VECTORS_--_...), then when you run another SCF calculation in a larger basis set and use "vectors input" to pick the movecs from the smaller calculation up. At that point NWChem should automatically perform this projection to create the start vectors.
Huub

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Hi Huub,

Thanks for the suggestion. I tried this and the program has not crashed but I am dubious that any projection has occurred. The reason I am suspicious is that the molecule I am working with is an open shell doublet and the SCF can converge erroneously to a higher energy solution. With a small basis set it has no problem in finding the correct solution and I can tell it is the correct solution by looking at the S^2 value. For the smaller basis set (6-311G**) the S^2 value is 0.7553 and the total energy is -398.225929335025 Hartree. If I perform the calculation with the larger basis set (6-311+G(2d,2p)) without any reading in of the vectors then the S^2 value is 1.1236 and the total energy is -398.113823075940 ---->>>> yes that is HIGHER in energy than it is with the smaller basis set <<------ This is because the SCF is stuck in a meta-stable solution. This has nothing to do with loose convergence criteria either, for example this is the final iteration:

41 -398.1138230759 8.43D-08 9.58D-09 605.6


So this is where the idea for projection comes in. If I try your suggestion above I get the same answer as if I didn't read anything in. To me this suggests that no projection has happened. Is there any other things that I could do here?

The documentation you sent me has the following directive for projection:

vectors input project "small basis" small.movecs

but if I do this the NWchem crashes

Thanks Geoff.

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Dear Geoff;

Recently I had a similar problem, and playing with following parameters solved it.
SWAP ALPHA .... + SWAP BETA .... + ADAPT OFF (I had symmetry)
The swapping, I did on the frontier orbital (HOMO--LUMO).
my molecule had about 60-70 atoms.

For me also smaller basis was fine but with DZVP failed.
It may also works for you.(Just an idea)

Shahab
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Example of project small basis to a larger one
Geoff/Shahab,
Have a look at the example below for projection molecular orbitals from a small basis to a larger one.
Among the key ingredient that are needed: definition of both the smaller and the larger basis set, plus mention of the small basis set in the "input project" line.

Cheers, Edo

start he

geometry
 he 0 0 0
 symmetry oh
end

basis  small
 * library sto-3g
end
basis  large
 * library 3-21g
end

set "ao basis" small
dft
 vectors input atomic output small.mos
end
task dft  

set "ao basis" large
dft
 vectors input project small small.mos output large.mos
end
task dft 

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Dear Shahab and Edo,

Thank you very much for these suggestions I will try them out and post back here for the good of the community.


Geoff.
Edited On 6:41:20 AM PDT - Wed, Sep 11th 2013 by Gpw501

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So I tried out both suggestions and the projection Edo suggested works out.. thanks. Though I would suggest that the documentation reflects how to do this.

Thanks a lot everyone.

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triple projection of basis set
Can I do a triple projection here. For example

set "ao basis" small

scf
vectors output a.movecs
end

task scf

set "ao basis" small

dft
vectors input a.movecs output b.movecs
end

task dft optimize

set "ao basis" large

dft
vectors input b.movecs
end

task dft optimize

I got an error while doing so. But not sure if it is due to possibility of triple projection.


basis directive body format is:
      tag library <standard set> [file <filename>]
[except <exceptions list>] [rel]
tag <contraction type> [rel]
<exponent> <contraction coefficients>
...
end basis


or
ecp directive body format is:
tag library <standard set> [file <filename>]
[except <exceptions list>] [rel]
tag nelec <number of electrons replaced on tag>
tag <contraction type>
<exponent> <contraction coefficients>
...
end ecp


or
so directive body format is:
tag library <standard set> [file <filename>]
[except <exceptions list>] [rel]
tag <contraction type>
<exponent> <contraction coefficients>
...
end so
------------------------------------------------------------------------
bas_input_body: format error in the input 0
------------------------------------------------------------------------
------------------------------------------------------------------------
current input line :
25: basis large cartesian
------------------------------------------------------------------------
------------------------------------------------------------------------
There is an error in the input file

Forum Vet
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Posts 1389
You should post the full input file.
With the information provided, it's hard to tell what is going on.


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