Influence of an electric‐field on the topological stability of the neutral lithium dimer

Abstract In this investigation, we seek to understand the role of non‐nuclear attractors ( NNA s) of the neutral Li 2 dimer subjected to an electric (± E ) field that is directed parallel ( ±E x ) and perpendicular ( ±E y ) to the bond‐path. The ±E x ‐fields and ±E y ‐fields are separately applied to the Li 2 molecular graph until the bond ruptures. The next generation quantum theory of atoms in molecules (NG‐QTAIM) interpretation of bonding was constructed with the stress tensor σ ( r ) eigenvectors on the Hessian of ρ ( r ) molecular graph. The asymmetry induced by both the ±E y ‐field and ±E x ‐field was detected in terms of the rotation of the orthogonal triad of stress tensor σ ( r ) eigenvectors { e 1σ , e 2σ , e 3σ } relative to the Cartesian coordinate frame. The orthogonal triad of Hessian of ρ ( r ) eigenvectors { e 1 , e 2 , e 3 } however, were only able to detect rotation induced by the high degree of asymmetry present for bent bond‐paths induced by the ±E y ‐fields. Larger movement of the NNA s along the bond‐path correlated with greater bond critical point ( BCP ) bond metallicity ξ( r b ). The effect of applying the ±E x ‐field was compared with unpublished results on neutral Li 2 subject to a stretching distortion. The lack of NNA motion along the bond‐path for the stretching distortion correlated with a lower degree of bond metallicity ξ( r b ). The stress tensor σ ( r ) eigenvectors have a unique ability to detect rotation relative to the Cartesian coordinate frame for high bond‐path symmetry occurring for the bond‐stretching distortion and application of the ±E x ‐field. Suggestions for future work are provided.