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

Abstract

AbstractIn this investigation, we seek to understand the role of non‐nuclear attractors (NNAs) of the neutral Li2dimer subjected to an electric (±E) field that is directed parallel (±Ex) and perpendicular (±Ey) to the bond‐path. The±Ex‐fields and±Ey‐fields are separately applied to the Li2molecular graph until the bond ruptures. The next generation quantum theory of atoms in molecules (NG‐QTAIM) interpretation of bonding was constructed with the stress tensorσ(r) eigenvectors on the Hessian ofρ(r) molecular graph. The asymmetry induced by both the±Ey‐field and±Ex‐field was detected in terms of the rotation of the orthogonal triad of stress tensorσ(r) eigenvectors {e1σ,e2σ,e3σ} relative to the Cartesian coordinate frame. The orthogonal triad of Hessian ofρ(r) eigenvectors {e1,e2,e3} however, were only able to detect rotation induced by the high degree of asymmetry present for bent bond‐paths induced by the±Ey‐fields. Larger movement of theNNAs along the bond‐path correlated with greater bond critical point (BCP) bond metallicity ξ(rb). The effect of applying the±Ex‐field was compared with unpublished results on neutral Li2subject to a stretching distortion. The lack ofNNAmotion along the bond‐path for the stretching distortion correlated with a lower degree of bond metallicity ξ(rb). The stress tensorσ(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±Ex‐field. Suggestions for future work are provided.