Difficulties using the esp module

From NWChem

Viewed 1827 times, With a total of 2 Posts
Jump to: navigation, search

  • Guest -
    Send PM
I need to assign partial charges to the atoms in my metal and metal-oxide clusters in order to develop an MD potential. Of course, these systems can have a large number of degenerate states. Spherical basis sets are of course very helpful in reducing the degeneracy (also setting the number of degenerate states to be zero helps, but causes it's own problems). I know that the manual states that only cartesian basis sets can be used, but the cartesian functions often result in incorrect ground state occupations and energies. Is there any workaround that would enable me to use spherical functions to perform an esp analysis? Is there alternative software that could be utilized such as a bader analysis?

Another problem I have had performing esp analyses (even using cartesian functions) on low-symmetry systems, I often encounter the error:
Quote:username

carttrans: ld lt lmax 70006

current input line
58: task esp

This type of error is most commonly associatated with calculations not reaching convergence criteria



Another, unrelated question is that to improve convergence of these metal and metal oxide clusters, I would like to try the fragment initial guess but, in certain cases, the restriction that the sum of the multiplicity of the fragments must equal the multiplicity of the molecule is not possible. A case of this situation is a neutral Ni_2 molecule which has a multiplicity of 3, just like the constituent atoms.
is there any way around this?

  • Bert Forum:Admin, Forum:Mod, NWChemDeveloper, bureaucrat, sysop
    Profile
    Send PM
Forum Vet
Threads 4
Posts 597
1. Where does it say in the ESP that only cartesian functions can be used?

2. Can you send me an input deck that fails with the lmax error. I think you are going beyond l=5 in angular momemtum. If so, we need to fix the code. Found one place that explicitly sets this to a max of 5.

Bert


Quote: Jul 18th 4:35 am
I need to assign partial charges to the atoms in my metal and metal-oxide clusters in order to develop an MD potential. Of course, these systems can have a large number of degenerate states. Spherical basis sets are of course very helpful in reducing the degeneracy (also setting the number of degenerate states to be zero helps, but causes it's own problems). I know that the manual states that only cartesian basis sets can be used, but the cartesian functions often result in incorrect ground state occupations and energies. Is there any workaround that would enable me to use spherical functions to perform an esp analysis? Is there alternative software that could be utilized such as a bader analysis?

Another problem I have had performing esp analyses (even using cartesian functions) on low-symmetry systems, I often encounter the error:
Quote:username

carttrans: ld lt lmax 70006

current input line
58: task esp

This type of error is most commonly associatated with calculations not reaching convergence criteria



Another, unrelated question is that to improve convergence of these metal and metal oxide clusters, I would like to try the fragment initial guess but, in certain cases, the restriction that the sum of the multiplicity of the fragments must equal the multiplicity of the molecule is not possible. A case of this situation is a neutral Ni_2 molecule which has a multiplicity of 3, just like the constituent atoms.
is there any way around this?

  • Guest -
    Send PM
ESP module works with spherical basis sets
Thanks so much for fixing the ESP module. It now works with spherical basis sets.


Forum >> NWChem's corner >> Running NWChem



Who's here now Members 0 Guests 1 Bots/Crawler 0


AWC's: 2.5.10 MediaWiki - Stand Alone Forum Extension
Forum theme style by: AWC