Spin-orbit splitting for inner-shell 2p states.

Area of Science:

• Quantum Chemistry
• Atomic and Molecular Physics
• Spectroscopy

Background:

• Calculating spin-orbit splitting is crucial for understanding electronic structure and spectroscopy.
• Accurate theoretical methods are needed for inner-shell transitions, which are complex.
• Previous methods may lack precision or computational efficiency for these systems.

Purpose of the Study:

• To present a new ab initio strategy for calculating spin-orbit splitting in inner-shell transitions.
• To establish a robust computational framework for analyzing complex electronic states.
• To apply the method to specific atomic and molecular systems.

Main Methods:

• Initial wave function calculation using a spinless Hamiltonian at a multiconfigurational level.
• Multireference configuration interaction to define singlet and triplet states at the 2p excitation edge.
• Diagonalization of the full Breit-Pauli Hamiltonian on the established state basis.
• Determination of spin-orbit splitting via a graphical procedure based on transition intensities.

Main Results:

• Successfully calculated spin-orbit splitting for inner-shell transitions using the novel ab initio method.
• Demonstrated the method's applicability to systems like argon, HCl, H2S, and PH3.
• Validated the graphical procedure for determining splitting based on transition intensity analysis.

Conclusions:

• The presented ab initio strategy provides an accurate and efficient means to compute spin-orbit splitting for inner-shell transitions.
• The method offers a valuable tool for theoretical investigations in atomic and molecular spectroscopy.
• The study successfully applies the developed technique to diverse chemical systems.