An ab initio variationally computed room-temperature line list for (32)S(16)O3

Area of Science:

• Theoretical Chemistry
• Spectroscopy
• Atmospheric Science

Background:

• Sulfur trioxide (SO3) is a key atmospheric molecule.
• Accurate spectroscopic data is crucial for atmospheric modeling and remote sensing.
• Previous theoretical calculations may lack the precision required for detailed analysis.

Purpose of the Study:

• To compute highly accurate ab initio potential energy and dipole moment surfaces for SO3.
• To generate a comprehensive line list for pure rotational and rotation-vibration spectra of SO3.
• To provide a reliable dataset for atmospheric and planetary spectroscopy.

Main Methods:

• Utilized the CCSD(T)-F12b level of theory with triple-zeta basis sets for surface calculations.
• Employed the variational nuclear motion program TROVE for spectral computations.
• Calculated transitions from 0-4000 cm(-1) with rotational states up to J = 85.

Main Results:

• Generated an extensive line list of 174,674,257 transitions for SO3.
• Achieved good agreement between calculated and observed infrared absorption spectra.
• Provided a list of 10,878 experimental transitions for spectroscopic databases.

Conclusions:

• The computed SO3 spectra are suitable for modeling room-temperature atmospheric conditions.
• The theoretical calculations enable the scaling of measured intensities to an absolute scale.
• The comprehensive line list enhances the understanding of SO3 in atmospheric and planetary environments.