Merge pull request #163 from marco-2023/zero_e_mults

Add zero electron species multiplicities

Clean up run and test modules.

Fix NIST dataset tests.

Calculate the energy for anions with charge -1.

Fix variable being returned by attribute atmass.

Add zero-electron species to gaussian dataset (#138)

Merge pull request #139 from theochem/fix_slater

Simplify and fix eval_ked_positive_definite for slater db

Simplify and fix eval_orbs_ked_positive_definite for slater db

Merge pull request #131 from theochem/add_laplacian

Add backward numpy compatibility to test_numerical_hf_atomic_density

Fix log density spline extrapolation (#133)

Change kwd argument to positional argument in helper function.

Support promolecules with single atom (#135)