A variationally computed room temperature line list for AsH₃.

Area of Science:

• Molecular Spectroscopy
• Computational Chemistry
• Quantum Mechanics

Background:

• Accurate molecular modeling is crucial for understanding chemical properties.
• Spectroscopic data provides vital insights into molecular structure and dynamics.
• Previous calculations for arsine lacked the desired accuracy.

Purpose of the Study:

• To compute highly accurate rotation-vibration energy levels and transition intensities for arsine.
• To refine theoretical models using experimental data for improved predictive power.
• To generate a reliable dipole moment surface for arsine.

Main Methods:

• Ab initio electronic structure calculations to generate a potential energy surface (PES).
• Refinement of the PES using experimental spectroscopic data.
• Calculation of rovibrational states and absolute line intensities using the refined PES and a new dipole moment surface (DMS).

Main Results:

• Achieved sub-wavenumber accuracy for arsine energy levels up to 6500 cm-1.
• Reproduced 578 experimental energies with a root-mean-square error of 0.122 cm-1.
• Computed dipole moment surface accurately predicts experimental line intensities for ν1 and ν3 bands within 10% uncertainty.

Conclusions:

• The refined theoretical model provides highly accurate predictions for arsine's spectroscopic properties.
• The calculated absorption cross-sections align well with experimental measurements.
• This work offers a valuable resource for future studies involving arsine spectroscopy.