Origin independent current density vector fields induced by time-dependent magnetic field. I. The LiH molecule

Area of Science:

• Quantum Chemistry
• Theoretical Physics
• Molecular Spectroscopy

Background:

• Understanding electronic current density is vital for molecular properties.
• Previous methods faced challenges with origin dependency and diamagnetic contributions.
• Optical magnetic fields induce complex electronic responses in molecules.

Purpose of the Study:

• To develop an origin-invariant theoretical method for calculating induced electronic current density.
• To computationally model the electronic current density in molecules under optical magnetic fields.
• To analyze the topological features of the induced current density field.

Main Methods:

• A theoretical method based on the continuous translation of the origin was employed.
• A computational scheme was developed to annihilate diamagnetic contributions.
• The electric quadrupole approximation was used for spatially uniform fields.
• The method was applied to the lithium hydride molecule.

Main Results:

• The induced electronic current density was found to be invariant of the origin.
• The computational scheme successfully removed conventional diamagnetic contributions.
• Analysis of lithium hydride revealed distinct current density structures at various magnetic field frequencies.
• Stagnation graphs were used to characterize the topological features of the vector field.

Conclusions:

• The developed theoretical method provides an accurate and origin-invariant calculation of induced electronic current density.
• The study verifies fundamental physical requirements like the continuity equation and Poincaré-Hopf theorem.
• The findings offer a new tool for investigating molecular responses to optical magnetic fields.