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Computation of Atmospheric Concentrations of Molecular Clusters from ab initio Thermochemistry
Published on: April 8, 2020
Parameterizations for ice nucleation in biological and atmospheric systems.
Thomas Koop1, Bernhard Zobrist
1Department of Chemistry, Bielefeld University, Bielefeld, Germany. thomas.koop@uni-bielefeld.de
Physical Chemistry Chemical Physics : PCCP
|November 20, 2009
Summary
This study compares two models for ice nucleation, finding that the water-activity-based approach is more universally applicable than the lambda approach for predicting ice nucleation in various solutions and biological systems.
Area of Science:
- Environmental science
- Biophysics
- Physical chemistry
Background:
- Ice nucleation is critical in atmospheric and biological systems.
- Understanding homogeneous and heterogeneous ice nucleation is essential for predicting freezing behavior.
Purpose of the Study:
- To evaluate the applicability of the lambda and water-activity-based approaches for heterogeneous ice nucleation.
- To investigate the influence of solutes and ice nuclei types on ice nucleation.
- To apply these models to biological systems, including freeze-tolerant and freeze-avoiding species.
Main Methods:
- Experimental analysis of heterogeneous ice nucleation using mineral dust and Snomax (Pseudomonas syringae) in solutions with various solutes.
- Concentration-dependent studies of ice nucleation temperature.
- Application of lambda and water-activity-based models to experimental data and biological freezing points.
Main Results:
- Ice nucleation temperature and lambda values are dependent on both ice nucleus and solute type.
- The water-activity-based approach's predictions depend solely on the ice nucleus type when water activity is known.
- Both models successfully describe the freezing behavior of freeze-tolerant and freeze-avoiding species.
Conclusions:
- The water-activity-based approach offers a more generalized framework for heterogeneous ice nucleation compared to the lambda approach.
- These models provide valuable tools for interpreting experimental freezing data in diverse biological contexts.
- The study highlights the importance of considering solute-specific effects in ice nucleation.
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