The Bloch equation with terms induced by an electric field

Area of Science:

• Nuclear Magnetic Resonance Spectroscopy
• Quantum Mechanics
• Computational Chemistry

Background:

• The Bloch equation describes nuclear magnetization dynamics.
• Molecules with permanent electric dipole moments are influenced by electric and magnetic fields.
• Understanding spin dynamics is crucial for molecular property determination.

Purpose of the Study:

• To derive the Bloch equation for nuclear magnetization in molecules with electric dipole moments under combined electric and magnetic fields.
• To establish a method for determining molecular dipole moment orientation.
• To investigate the impact of electric fields on spin dynamics.

Main Methods:

• Derivation of the Bloch equation for spin-1/2 nuclei.
• Utilizing nuclear magnetic shielding tensor and dipole moment information.
• Applying oscillating electric fields at half the spin precession frequency.
• Performing four-component relativistic density functional theory computations.

Main Results:

• A method is presented to determine dipole moment orientation by measuring transverse nuclear magnetization.
• Electric field perturbation coefficients of the relaxation matrix are calculated for heavy-atom molecules.
• Perturbations are shown to be experimentally observable at specific electric (5 kV/mm) and magnetic (10 T) field strengths.

Conclusions:

• The study provides a theoretical framework and computational evidence for orienting molecular dipole moments using spin dynamics.
• The findings suggest experimental feasibility for probing molecular structure and dynamics with combined electric and magnetic fields.
• This approach offers a novel pathway for molecular characterization in physical chemistry and spectroscopy.