2026-10-12T09:27:04Z https://api.figshare.com/v2/oai

oai:figshare.com:article/33969152 2026-09-22T23:03:32Z category_1 category_4 category_21 category_873 category_734 category_931 category_811 category_135 portal_63 item_type_3 month_year_09_2026

Achieving Near-Chemical Accuracy with Atom-Centered Potential-Augmented M06-2X Zhehan Jia (21010017) Mahsa Nazemi-Ashani (21876936) Alberto Otero-de-la-Roza (1299720) Gino A. DiLabio (1274490) Biophysics Biochemistry Biotechnology Chemical Sciences not elsewhere classified Biological Sciences not elsewhere classified Information Systems not elsewhere classified Mathematical Sciences not elsewhere classified Computational Biology yield results comparable demonstrating excellent performance accurate thermodynamic properties elucidating reaction mechanisms moderately large systems little additional cost reaction free energies sized basis sets density functional theory thermochemical calculations based 2x density functional basis set combination reaction energies thermochemical calculations basis sets basis set molecular systems low cost parametrization set uncorrected functional mitigating functional realistic sizes rate constants previous works previous studies magnitude errors higher level essential tool equilibrium constants electron potentials correlation functionals commonly employed common exchange centered potentials centered potential barrier heights achieving near 1 kcal The calculation of accurate thermodynamic properties, such as activation and reaction free energies, is an essential tool for elucidating reaction mechanisms. The method most commonly employed, density functional theory (DFT), generally falls short of chemical accuracy (1 kcal/mol error), resulting in order-of-magnitude errors in the calculation of equilibrium constants and rate constants. The inaccuracy of common exchange-correlation functionals is compounded by the use of small and medium-sized basis sets, which are mandatory for molecular systems with realistic sizes. The basis set incompleteness error incurred by the use of these basis sets further diminishes the accuracy of thermochemical calculations. In previous works, we proposed energy corrections based on the use of atom-centered potentials (ACP) as a way of mitigating functional and basis set incompleteness error. ACPs are one-electron potentials that, when applied in combination with a functional and basis set, yield results comparable to a higher level of theory with little additional cost. In this work, and based on previous studies, we develop ACPs for thermochemical calculations based on the M06-2X density functional and the 6-31+G(d,p) basis. The resulting M06-2X/6-31+G(d,p)-ACP method is tested on a variety of cases, demonstrating excellent performance for thermochemistry and kinetics calculations well outside the parametrization set, particularly for reaction energies and barrier heights of moderately large systems. At the same time, M06-2X/6-31+G(d,p)-ACP retains the low cost of the uncorrected functional and basis set combination. 2026-09-22T00:00:00Z Dataset Dataset 10.1021/acs.jctc.6c01050.s002 https://figshare.com/articles/dataset/Achieving_Near-Chemical_Accuracy_with_Atom-Centered_Potential-Augmented_M06-2X/33969152 CC BY-NC 4.0