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Statistical molecular fragmentation: which parameters influence the branching ratios?
Pierre Désesquelles1, Nguyen-Thi Van-Oanh, Sébastien Thomas
1Laboratoire de Physique des Gaz et des Plasmas, Univ. Paris-Sud, CNRS, Université Paris-Saclay, 91405, Orsay, France.
Physical Chemistry Chemical Physics : PCCP
|December 11, 2019
Summary
Statistical models effectively study thermodynamically controlled molecular fragmentation. The Statistical Molecular Fragmentation model shows branching ratios are most sensitive to vibrational frequencies, not molecular descriptions from ab initio methods.
Area of Science:
- Chemical Physics
- Computational Chemistry
- Physical Chemistry
Background:
- Thermodynamically controlled molecular fragmentation yields can be studied using statistical models.
- Understanding fragmentation pathways is crucial for predicting chemical reaction outcomes.
Purpose of the Study:
- To investigate parameters influencing branching ratios in molecular fragmentation.
- To apply the Statistical Molecular Fragmentation (SMF) model to propane decomposition.
Main Methods:
- Utilized the Statistical Molecular Fragmentation (SMF) model.
- Analyzed the decomposition of propane.
- Compared results from various ab initio methods (B3LYP, CCSD(T), composite methods with different basis sets).
Main Results:
- Fragmentation process showed low sensitivity to differences in molecular descriptions from common ab initio methods.
- Branching ratios were found to be highly sensitive to vibrational frequencies of molecules and radicals.
- The SMF model successfully applied to propane decomposition.
Conclusions:
- Vibrational frequencies are the dominant factor controlling branching ratios in thermodynamically controlled fragmentation.
- The choice of ab initio method has a limited impact on fragmentation branching ratios.
- The SMF model provides a robust framework for studying molecular fragmentation dynamics.
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