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Communication: Multi-state analysis of the OCS ultraviolet absorption including vibrational structure
J A Schmidt1, M S Johnson, G C McBane
1Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen Ø, Denmark. johanalbrechtschmidt@gmail.com
The Journal of Chemical Physics
|April 10, 2012
Summary
This study analyzes the first absorption band of carbonyl sulfide (OCS). The research reveals distinct vibrational structures attributed to specific electronic state excitations at different energy levels.
Area of Science:
- Physical Chemistry
- Spectroscopy
- Quantum Chemistry
Background:
- Carbonyl sulfide (OCS) exhibits complex absorption spectra.
- Understanding these spectra is crucial for atmospheric chemistry and molecular physics.
Purpose of the Study:
- To analyze the first absorption band of OCS.
- To elucidate the electronic and vibrational origins of spectral features.
Main Methods:
- Computational analysis using potential energy surfaces.
- Calculation of transition dipole moment functions for singlet and triplet states.
- Theoretical modeling of spectral excitation pathways.
Main Results:
- The 2 (1)A' state is the primary excitation pathway for most photon energies.
- Vibrational structures in the band's center originate from the 2 (3)A'' triplet state.
- Low-energy spectral features are linked to bending excitations in the 2 (1)A' and 1 (1)A'' states.
Conclusions:
- The study successfully assigns spectral features to specific electronic and vibrational transitions in OCS.
- Provides a detailed theoretical framework for interpreting OCS absorption spectra.
- Highlights the significant contribution of triplet states to OCS absorption.
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