Valence universal multireference coupled cluster (VUMRCC) method suffers from numerical divergence owing to intruder states in inner valence region of molecules. Eigenvalue independent partitioning (EIP) technique in Fock space converts VUMRCC equations to a non-Hermitian eigenvalue problem [29]. EIP makes access to the roots invaded by intruders much easier. The EIP-VUMRCC determines with significant precision the potential energy curve of the strongest bonding and inner valence 2 sigma gMO of N2+ ion. Inclusion of full connected triple excitation CC operators is found very crucial. In ground state, perturbative (T) over cap (3) is considered by CCSDT1-a approximation. (C) 2015 Published by Elsevier B.V.