Electronic and Vibrational Spectroscopy of CsS

Area of Science:

• Theoretical Chemistry
• Computational Physics
• Molecular Spectroscopy

Background:

• Accurate potential energy curves (PECs) are crucial for understanding molecular behavior.
• Diatomic molecules like Cesium Sulfide (CsS) serve as fundamental systems for theoretical study.
• The influence of electron correlation and spin-orbit coupling on PECs requires detailed investigation.

Purpose of the Study:

• To compute and analyze the potential energy curves (PECs) of the lowest electronic states of the diatomic CsS molecule.
• To investigate the impact of electron correlation and spin-orbit effects on the PECs and spectroscopic properties of CsS.
• To characterize the unique "bowl" potential of the 2^2Π state and its implications for molecular dynamics.

Main Methods:

• Utilized multi-configurational ab initio methodologies.
• Employed internally contracted multireference interaction configuration including Davidson correction (MRCI+Q).
• Calculations were performed with and without spin-orbit effects to assess their influence.

Main Results:

• Computed PECs for the lowest electronic states of CsS, highlighting interactions between ionic and neutral dissociation limits.
• Demonstrated the critical importance of including extensive electron correlation for accurate PECs and spectroscopy.
• Observed significant alterations in PECs and spectroscopic parameters due to spin-orbit interaction.
• Identified a "bowl"-shaped potential for the 2^2Π state, suggesting potential for strong wavepacket oscillations.

Conclusions:

• The study provides accurate PECs and spectroscopic parameters for CsS, crucial for experimental validation.
• Spin-orbit coupling plays a vital role in shaping the electronic structure and properties of CsS.
• The unique "bowl" potential of the 2^2Π state offers exciting prospects for studying molecular dynamics and state couplings.