The molecular electric quadrupole moment of N 2

Abstract

From accurate ab initio calculations in hierarchies of basis sets and wavefunction models, the non-relativistic CCSD(T) basis set limit value of the equilibrium molecular electric quadrupole moment ( Θ e ) of N 2 has been determined. Including estimates of the small effects of relativity and correlation beyond CCSD(T), the value obtained is Θ e = (−4.99±0.03)×10 −40 Cm 2. The corresponding rovibrationally averaged value Θ 0 = (−4.93±0.03)×10 −40 Cm 2 is in disagreement with the recent experimental value of (−4.65±0.08)×10 −40 Cm 2. The latter, however, is deduced from the measured effective Θ via a correction term, whose value is questionable. Using a more accurate value for the correction term we obtain the improved experimentally based value (−5.01±0.08)×10 −40 Cm 2, which is in good agreement with our theoretical value.