Nonperturbative ab initio calculations in strong magnetic fields using London orbitals

Area of Science:

• Computational chemistry
• Quantum mechanics
• Molecular modeling

Background:

• Accurate calculation of molecular properties in strong magnetic fields is challenging.
• Existing methods often struggle with gauge-origin dependence and nonperturbative effects.

Purpose of the Study:

• To develop a self-consistent field (SCF) London-orbital computational scheme for gauge-origin independent, nonperturbative calculations.
• To enable accurate studies of molecular responses in strong magnetic fields.

Main Methods:

• A novel SCF London-orbital scheme was implemented.
• Molecular integrals were evaluated over field-dependent basis functions, akin to a hybrid Gaussian and plane-wave basis set.
• The McMurchie-Davidson scheme was adapted for calculating molecular integrals over London orbitals.

Main Results:

• Preliminary calculations of fourth-rank hypermagnetizabilities for small molecules, benzene, and cyclobutadiene were performed.
• The nonperturbative approach demonstrated its utility for highly nonlinear responses.

Conclusions:

• The developed computational scheme provides a robust method for studying molecules in strong magnetic fields.
• This approach is particularly valuable for investigating paramagnetic closed-shell systems and pi-electron responses.