CCSD energy and bsse energy error

[Zakhar Lyullin]

Dear all,
I am still trying to calculate interaction potentials for various pairs of atoms, it is necessary for the calculation of scattering parameters. (My previous question was here  https://groups.google.com/g/nwchem-forum/c/4yx7eF6Msp0/m/Wu8FiAZgAQAJ)
Now I face the following problem, a calculation that is usually completed correctly ends with the following error:

For Al with Ne
ccsd_energy_loc: maxiter exceeded                 101

For Be with Ne
bsse_energy: no geometry                    0
This error has not yet been assigned to a category

But this happens only in a certain range of distances between atoms. These calculations are correctly performed at other distances, for example 7.0 between atoms, in the input file only positions of atoms were changed.
For your convenience please find below the input file used in calculations. Looking to receive any suggestions how to solve it.

Al with Ne
_________________________________________________
memory total 100000 mb
memory stack 15000 mb heap 15000 mb global 30000 mbgeometry
Al 0.00000 -1.800 0.00000
Ne 0.00000 1.800 0.00000
  symmetry csendbasis
    Al library aug-cc-pVQZ
    bqAl library Al aug-cc-pVQZ
    Ne library aug-cc-pVQZ
    bqNe library Ne aug-cc-pVQZ
endbsse
    mon metal 1
    mult 2    mon gas 2
endscf
  rohf
  doublet
endtask scftce
 freeze atomic
 ccsd(t)
endtask tce

Be with Ne
_________________________________________________
memory total 100000 mb
memory stack 15000 mb heap 15000 mb global 30000 mbgeometry
        Be  0.00000   0.00000   0.00000
        Ne  0.00000   0.00000   3.600
endbasis
    Be library aug-cc-pVQZ
    bqBe library Be aug-cc-pVQZ
    Ne library aug-cc-pVQZ
    bqNe library Ne aug-cc-pVQZ
endbsse
    mon metal 1
    mon gas 2
endscf
  uhf
endtask scftask ccsd(t)

[Edoardo Aprà]

Did you try to switch to spherical basis (the default is cartesian)?

https://nwchemgit.github.io/Basis.html#-spherical-or-cartesian

basis spherical

    Al library aug-cc-pVQZ
    bqAl library Al aug-cc-pVQZ
    Ne library aug-cc-pVQZ
    bqNe library Ne aug-cc-pVQZ
end

[Zakhar Lyullin]

No, I didn't try. And it really helped. And I am very grateful to you.
Dear Edoardo, thank you very much for clarifying this!

четверг, 6 января 2022 г. в 22:57:19 UTC+3, Edoardo Aprà: