C₃H₈O₂ Isomers: Insights into Potential Interstellar Species

Area of Science:

• Astrochemistry
• Computational Chemistry
• Quantum Chemistry

Background:

• 2-Methoxyethanol (C3H8O2) detected in protocluster NGC 6334I.
• Structural isomers 1,2- and 1,3-propanediol remain undetected in Sgr B2.
• Investigating C3H8O2 isomers is crucial for understanding interstellar chemistry.

Purpose of the Study:

• To explore the potential energy surface of C3H8O2 isomers.
• To identify stable C3H8O2 isomers relevant to the interstellar medium (ISM).
• To assess the stability of geminal diols under interstellar conditions.

Main Methods:

• High-level quantum chemical calculations (CCSD(T)/aug-cc-pVTZ//MP2/aug-cc-pVTZ).
• Exploration of the C3H8O2 potential energy surface.
• Analysis of gas-phase decomposition barriers.

Main Results:

• Identified 11 C3H8O2 species.
• Determined geminal diols (2,2- and 1,1-propanediol) as the most stable forms.
• 1,1-Propanediol found to be thermodynamically stable at low temperatures (10-150 K).

Conclusions:

• Geminal diols are the most stable C3H8O2 isomers.
• 1,1-Propanediol's stability at low temperatures suggests potential presence in the ISM.
• C3H8O2 isomers below 30 kcal/mol are relevant to ISM chemistry.