Self-Consistent Component Increment Theory for Predicting Enthalpy of Formation

The
gas-phase enthalpy of formation (ΔHf) plays a fundamental role in predicting reaction thermodynamics
and constructing kinetic models. With advances in computational power
and method development, chemically accurate quantum chemistry methods
that can predict ΔHf values for
small molecules are available; however, large molecules are still
out of reach. Increment theories provide a means of extending the
prediction capability of high-level methods by decomposing the molecular
ΔHf into the additive contributions
from individual atoms, bonds, groups, or components. Here, we introduce
a novel component increment theory, topology-automated force–field
interaction component increment theory (TCIT), in which all component
contributions are derived exclusively from Gaussian-4 (G4) results
for algorithmically generated model compounds. In a benchmark evaluation
of noncyclic compounds from the Pedley, Naylor, and Kline experimental
ΔHf dataset, TCIT exhibits consistently
lower signed and absolute errors compared with the conventional Benson
group increment theory (BGIT). These results pave the way for future
extensions of TCIT to ring-containing, ionic, and radical species
for which experimental data scarcity currently limits the application
of BGIT.