Integration of global ring currents using the Ampère-Maxwell law.

Area of Science:

• Computational Chemistry
• Quantum Chemistry
• Spectroscopy

Background:

• Magnetically induced ring currents are crucial for understanding aromaticity.
• Existing methods for calculating ring currents can be computationally intensive or limited in scope.

Purpose of the Study:

• To develop and validate a new method for calculating magnetically induced ring currents.
• To demonstrate the feasibility of this method across various molecular types.
• To establish a relationship between ring currents and nucleus-independent chemical shifts (NICS).

Main Methods:

• Calculation of magnetic shielding tensors using the Ampère-Maxwell law.
• Integration of the zz component of the shielding tensor along molecular symmetry axes.
• Comparison with ring-current strengths obtained via current-density flux integration.

Main Results:

• The proposed method accurately calculates ring currents for aromatic, antiaromatic, and nonaromatic molecules.
• Results show perfect agreement with established current-density flux methods.
• A direct relationship was found between NICS values and the spatial derivative of global ring-current strength.

Conclusions:

• The new method provides a robust and versatile approach to quantify magnetically induced ring currents.
• This technique is compatible with various electronic structure codes.
• The established link between NICS and ring currents offers new insights into electronic structure analysis.