Calculation of ground and excited state potential energy curves of the MgAr complex using the coupled cluster approximate triples model CC3

Potential curves of the ground and six excited states of MgAr are analysed using the coupled cluster approximate triples approach CC3. The ground state curve is obtained from conventional closed shell energy calculations, and excitation energies to the electronically excited states are obtained solving the CC3 response eigenvalue equation, yielding the potential curves for the excited states. The computed spectroscopic parameters (Re, ωe, D0 and T0) are in good agreement with experimental data when sufficiently large basis sets are used and the counterpoise correction is applied.