Use "calcfc" in Gaussian only for non monoatomic species

[alongd]

This PR removes the Gaussian "calcfc" keyword from the opt keyword list for monoatomic species. Issue detected by @mjohnson541, fix suggested by @dranasinghe

fixes #435

[codecov]

Codecov Report

Merging #436 (28a5fc8) into master (20e68d2) will decrease coverage by 0.01%.
The diff coverage is 0.00%.

@@            Coverage Diff             @@
##           master     #436      +/-   ##
==========================================
- Coverage   54.07%   54.06%   -0.02%     
==========================================
  Files          38       38              
  Lines       12112    12115       +3     
  Branches     3741     3742       +1     
==========================================
  Hits         6550     6550              
- Misses       4580     4583       +3     
  Partials      982      982              

Impacted Files	Coverage Δ
arc/job/job.py	21.72% <0.00%> (-0.07%)	⬇️

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[alongd]

@mjohnson541, could you approve that this addition fixes your issue?

[mjohnson541]

Unfortunately, this branch doesn't seem to fix it:

input.txt

output.txt

[mjohnson541]

So just running # cbs-qb3 geom=connectivity
seems to work properly, although ARC seems to have trouble recognizing that the output file is converged.