BasisSetNotFound, how should I avoid it

When making calculation, I encountered the following error, Are there any methods that I can avoid the error? I looked for solution in Web, but I can not find it, unfortunately. Thanks!

QcdbException BasisSetNotFound: BasisSet::construct: Unable to find a basis set for atom 1 for key BASIS among:
  Shell Entries: ['I']
  Basis Sets: [('6-31G(D)', '6-31G(D)', None)]

6-31G(D) doesn’t (according to the Basis Set Exchange, anyways) define a basis set for Iodine. Switch to a basis set that supports Iodine. You can find a list on the basis set exchange. The question of “which basis set should I use?” depends, as always, on what your electronic structure method is. For DFT, high accuracy results require a thorough benchmark study to determine the most appropriate functional/basis combination at an acceptable speed.

Thank you for your comment, I found “Basis Set Exchange”. Do everyone download a missing bases file, e.g. 6-31G(D) for “I”? or, switch basis only for “I”, which is something like below? I’m not sure whether it is proper settings or not

#ene, wfn = optimization(“hf/sto-3g”, return_wfn=‘yes’)
#ene, wfn = optimization(“mp2/6-31G(d)”, return_wfn=‘yes’)
mybasis = ‘’’
assign 6-31G(d)
assign I sto-3g
psi4.basis_helper(mybasis , name='mybasis ')
ene, wfn = optimization(“mp2”, return_wfn=‘yes’)

The correct answer here is probably not to use 6-31G(d) at all; it is very rarely a good basis set to use. I can’t know for sure without knowing more details of your project.

Can you reach out to others in your organization for more guidance? Basis set selection is something that new quantum chemists should be trained in, not left to figure out on their own.

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