Rationalizing polymorphism with local correlation-based methods: a case study of pnictogen molecular crystals.

Area of Science:

• Computational chemistry
• Materials science
• Solid-state chemistry

Background:

• Understanding molecular crystal stability is crucial for materials design.
• Predicting crystal structures and properties requires accurate computational methods.
• Analyzing intermolecular interactions is key to rationalizing crystal packing and stability.

Purpose of the Study:

• To develop and validate a computational workflow for quantifying and rationalizing the relative stability of molecular crystal structures.
• To utilize quantum chemical methods and cluster models for accurate energy estimations.
• To gain in-depth chemical insights into the intermolecular forces governing crystal stability.

Main Methods:

• Employed the Hartree-Fock plus London Dispersion (HFLD) scheme to estimate lattice energies.
• Utilized the fragment-pairwise Local Energy Decomposition (fp-LED) scheme to analyze intermolecular interactions.
• Applied the workflow to case studies including naphthyl-substituted dipnictanes and tris(thiophen-2-yl)bismuthane polymorphs.

Main Results:

• The HFLD and fp-LED schemes accurately quantify relative crystal stabilities.
• fp-LED successfully decomposes interactions into dispersion, electrostatics, and exchange components.
• The method requires only a single interaction energy computation per structure.

Conclusions:

• The proposed computational workflow offers high accuracy and valuable chemical insights.
• This approach facilitates the design of crystal structures with tailored properties.
• The methodology opens new avenues for studying molecular aggregates in materials science.