Electric quadrupole moments and electron affinities of atoms from H to Cl: a coupled-cluster study

Electric quadrupole moments and electron affinities of ground-state atoms from H to Cl are computed at the infinite-order coupled-cluster method with the noniterative (CCSD(T)) and iterative (CCSDT) inclusion of all single, double, and triple excitations, respectively. Generally, there exists some correlation between the magnitudes of quadrupole moments and electron affinities (A) of the atoms. The highest level of our calculations delivers an accuracy in the computed A values compared to experimental data not worse than 0.03 eV.