An accurate ab initio calculation of the electron affinity of NO

Potential energy curves for NO and NO− were calculated at the QCISD, QCISD(T), CCSD and CCSD(T) levels using aug-cc-pVDZ and aug-cc-pVTZ basis sets. The curves were fit with a modified Morse potential and rovibrational eigenvalues were extracted using TRIATOM software. The electron affinity of NO and the spectroscopic constants of both species were then determined. Better than 97% accuracy for the electron affinity was obtained for the QCISD, QCISD(T) and CCSD(T) techniques combined with the aug-cc-pVTZ basis set. It was determined that NO− is stable by virtue of zero-point energy only.