ETD

• astrochemistry
• excited-state properties
• strong magnetic fields
• theoretical chemistry

Strong magnetic fields profoundly modify the electronic structure of atoms and molecules by breaking spatial symmetries and introducing additional coupling terms that affect electron correlation. Consequently, accurate theoretical techniques are essential for the investigation of molecular systems under such extreme conditions. In this thesis, the machinery required to compute excited-state properties at the expectation-value level has been implemented within the EOM-CCSD framework in the QCUMBRE quantum chemistry package, thereby extending its capabilities for excited-state calculations in finite magnetic fields. The implementation has been applied to representative molecular systems relevant to the study of magnetic white dwarfs, demonstrating its ability to capture magnetic-field-induced changes in both state energies and electronic properties.