The nuclear quadrupole moment of 14N obtained from finite-element MCHF calculationson N2+ (2p; 2P32) and N+ (2p2; 3P2 and 2p2; 1D2)

The electric field gradient at the nucleus is evaluated for the title systems using finite-element multiconfiguration Hartree-Fock (MCHF) expansions as electronic wavefunctions. The new nuclear quadrupole moment for 14N (Q(14N)) from N2+ 2p; 2P32 is 20.44(3) mb, an order-of-magnitude improvement in accuracy over the previous standard value of 20.2(3) mb from N+ 2p3p; 1P1. The present Q(14N) is supported by the N+ 2p2; 3P2 and 2p2; 1D2 values of 20.45(6) mb and 20.48(8) mb.