Molecular structures with spectroscopic accuracy at DFT cost by the templating synthon approach and the PCS141 database
Year: 2025
Type: article
Abstract: The computation of accurate geometric parameters at density functional theory cost for large molecules in the gas phase is addressed through a novel strategy that combines quantum chemical models with machine learning techniques. The first key step is the expansion of a database of accurate semi-experimental equilibrium structures with additional molecular geometries optimized by version 2 of the Pisa composite scheme. Then, the templating synthon approach is used to improve the accuracy of structures optimized by a hybrid density functional paired with a double zeta basis set, leveraging chemical similarity to cluster different molecular environments and refine bond lengths and valence angles. A set of prototypical biomolecular building blocks is used to demonstrate that it is possible to achieve spectroscopic accuracy for molecular systems too large to be treated by state-of-the-art composite wavefunction methods. In addition, a freely accessible web-based tool has been developed to facilitate the post-processing of geometries optimized using standard electronic structure codes, thereby providing an accurate and efficient tool for the computational study of medium- to large-sized molecules, also accessible to experiment-oriented researchers.
Source: The Journal of Chemical Physics
DOI: 10.1063/5.0255564
Language: English
Subfield: Atomic and Molecular Physics, and Optics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W4408671986