Atom-bond pairwise additive representation for halide-benzene potential energy surfaces: an ab initio validation...

Area of Science:

• Computational Chemistry
• Physical Chemistry
• Quantum Chemistry

Background:

• Understanding molecular interactions and potential energy surfaces is crucial for studying noncovalent interactions and molecular dynamics.
• Semiempirical methods offer a computationally efficient approach to model these interactions.

Purpose of the Study:

• To extend a novel semiempirical method to investigate anion-benzene systems (X(-)-C(6)H(6)).
• To evaluate the accuracy of the semiempirical method against high-level ab initio calculations.
• To analyze the contributions of different components to the total interaction energy.

Main Methods:

• Developed a semiempirical method based on atom/ion-molecular bond interactions.
• Applied the method to X(-)-C(6)H(6) systems (X = F, Cl, Br, I).
• Validated results using second-order Møller-Plesset perturbation theory (MP2) ab initio calculations and symmetry-adapted perturbation theory (SAPT).

Main Results:

• The semiempirical method successfully reproduced key features of the potential energy surface for heavier anions (Cl(-), Br(-), I(-)) interacting with benzene.
• Binding energies for fluoride-benzene were underestimated due to limitations in modeling short-range electrostatic interactions with a point charge model.
• Analysis provided insights into the components of total interaction energy.

Conclusions:

• The developed semiempirical model shows promise for studying anion-aromatic interactions, particularly for heavier systems.
• Further refinement is needed to accurately capture short-range electrostatic interactions involving diffuse anions like fluoride.
• The study enhances understanding of anion-aromatic interactions and the capabilities of semiempirical methods.