Cellmetry: A first-principle pKa determination by plane-wave functions

We developed a methodology to analyze and determine acid dissociation pK(a) values by using plane wave functions and density functional theory. The periodicity of the PW functions allows us to scan the energies as well as the derived pK values. Explicit and implicit solvent effects were also taken into account to study the pK tendencies along the cell sizes. Some well-known molecules (water, ammonia, alcohols, peroxides, phenol, amines, and N-heterocyclic compounds) were studied which covered a wide range of structural/electronic properties to analyze the accuracy and the limit of the methodology. Some motifs were found by scanning the cell size-dependent pK values which belong to the cell size range where the experimental pK value or range can be found. Several strategies were carried out which can do good or even excellent (+/- 0.3) predictions for other compounds based on our study. Our detailed computational titration was made by the Quantum Espresso software package.

Automated summary

This article presents a methodology for analyzing and determining acid dissociation pK(a) values using plane wave functions and density functional theory. By scanning cell size-dependent pK values, certain patterns were identified and strategies were developed for predicting pK values of other compounds.