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Diabat method for polymorph free energies: Extension to molecular crystals
Kartik Kamat1, Rui Guo2, Susan M Reutzel-Edens3
1Department of Chemical Engineering, University of California-Santa Barbara, Santa Barbara, California 93106, USA.
The Journal of Chemical Physics
|December 31, 2020
Summary
We developed a novel mapping method to accurately calculate free energy differences between molecular crystal polymorphs using lattice-switch Monte Carlo. This approach simplifies complex calculations and validates the method
Area of Science:
- Computational chemistry
- Materials science
- Crystallography
Background:
- Lattice-switch Monte Carlo (LSMC) and diabat methods are effective for polymorph free energy calculations.
- Accurate free energy differences are crucial for understanding crystal behavior.
Purpose of the Study:
- Introduce a novel one-to-one mapping for molecular crystal polymorphs.
- Facilitate LSMC and related methods for free energy difference computations.
- Validate the mapping's accuracy and precision.
Main Methods:
- Developed a unitary one-to-one mapping between crystal polymorphs.
- Applied the mapping to LSMC and diabat methods.
- Computed free energy differences for benzene and carbamazepine polymorphs.
Main Results:
- The mapping is unitary, simplifying free energy calculations.
- The method is applicable to complex molecular crystals.
- Thermodynamic cycle calculations showed high precision, validating the approach.
Conclusions:
- The novel mapping enhances LSMC and diabat methods for polymorph free energy calculations.
- The method offers a force field-independent validation.
- Enables precise estimation of individual free energy differences.
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