High-Resolution Laser Photoacoustic Spectroscopy of OCS in the 12 000-13 000 cm(-1) Region

Area of Science:

• Molecular Spectroscopy
• Laser Physics
• Quantum Chemistry

Background:

• Carbonyl sulfide (OCS) is a molecule of interest in atmospheric and astrophysical studies.
• Accurate spectroscopic data is crucial for understanding molecular behavior and interactions.

Purpose of the Study:

• To record and analyze the near-infrared spectrum of OCS using advanced laser photoacoustic spectroscopy.
• To identify new vibrational bands and characterize their properties.
• To refine molecular models by incorporating new spectral data and analyzing perturbations.

Main Methods:

• Utilized a tunable titanium-sapphire laser coupled with a highly sensitive photoacoustic cell.
• Recorded OCS spectra in specific near-infrared regions (11953-12084 cm⁻¹, 12829-12890 cm⁻¹, 12998-13001 cm⁻¹).
• Performed band-by-band least-squares fits and global analysis including l-type resonance and anharmonic interactions.

Main Results:

• Successfully recorded the OCS spectrum with high sensitivity (αmin ≈ 10⁻⁹ cm⁻¹).
• Identified the previously reported 00(0)6-00(0)0 band of (16)O(12)C(32)S and several new weaker bands.
• Observed the 00(0)6-00(0)0 band of (16)O(12)C(34)S.
• Deduced effective state parameters and analyzed perturbations and intensity transfers.

Conclusions:

• The study provides a more complete spectroscopic characterization of OCS in the near-infrared.
• The new data and analysis enhance the understanding of molecular perturbations and intensity dynamics in OCS.
• This work contributes valuable data for further theoretical and experimental investigations of OCS.