Magnetically induced current density: a semiempirical approach.

Area of Science:

• Computational chemistry
• Quantum chemistry
• Theoretical chemistry

Background:

• Accurate calculation of magnetically induced current densities is crucial for understanding molecular electronic structure and aromaticity.
• Semiempirical methods offer a computationally efficient alternative to ab initio methods for electronic structure calculations.

Purpose of the Study:

• To evaluate the performance of various NDDO-based semiempirical methods for calculating current densities within the CTOCD-DZ framework.
• To propose and assess modifications to NDDO-based methods for reduced computational expense.

Main Methods:

• Utilized the CTOCD-DZ (continuous transformation of origin of current density-dimagnetic zero) approach.
• Employed various semiempirical methods based on the neglect of diatomic differential overlap (NDDO) approximation.
• Compared results against the B3LYP/def2-SVP reference for benzenoid hydrocarbons.

Main Results:

• Assessed the accuracy of different NDDO-based methods for calculating magnetically induced current densities.
• Demonstrated that modified NDDO-based approaches significantly decrease computational time.
• Showed that the modified methods maintain accuracy comparable to original approaches.

Conclusions:

• NDDO-based semiempirical methods are viable for calculating current densities.
• Modifications to these methods can substantially improve computational efficiency without sacrificing accuracy.
• The developed approach offers a faster route to studying magnetic properties of molecules.