Electronic Structure and Laser-Cooling Prospects of the AlCd Molecule: A Theoretical Study Including Spin-Orbit...

Area of Science:

• Computational Chemistry
• Molecular Physics
• Quantum Chemistry

Background:

• Understanding the electronic structure of diatomic molecules is crucial for predicting their chemical and physical properties.
• The AlCd molecule's electronic states and properties have not been extensively studied, necessitating detailed theoretical investigation.

Purpose of the Study:

• To computationally investigate the electronic structure of the AlCd molecule.
• To characterize the low-lying electronic states and determine their spectroscopic parameters.
• To assess the potential of AlCd for direct laser cooling applications.

Main Methods:

• Employed *ab initio* Complete Active Space Self-Consistent Field (CASSCF) and Multi-Reference Configuration Interaction with Single and Double Excitations plus Davidson correction (MRCI + Q) calculations.
• Computed adiabatic potential energy curves in both ^2S+1Λ^(+/-) and Ω representations.
• Performed rovibrational analysis using the canonical functions method.

Main Results:

• Calculated potential energy curves for low-lying doublet and quartet electronic states of AlCd.
• Determined spectroscopic parameters (T_e, R_e, ω_e, B_e, μ_e, D_e) for bound states.
• Characterized several new electronic states and obtained rovibrational constants (B_v, D_v, E_v, R_min, R_max).

Conclusions:

• The study provides a comprehensive theoretical characterization of the AlCd molecule's electronic structure.
• Identified key molecular properties and new electronic states, expanding the understanding of AlCd.
• Calculated Franck-Condon factors suggest potential for AlCd in direct laser cooling.