Accurate Potential Energy Surfaces Using Atom-Centered Potentials and Minimal High-Level Data.

Area of Science:

• Computational Chemistry
• Theoretical Chemistry
• Quantum Chemistry

Background:

• Accurate potential energy surfaces (PESs) are crucial for understanding molecular behavior.
• High-level computational methods for PESs can be computationally expensive.
• Developing efficient and accurate methods for PES calculations is an ongoing challenge.

Purpose of the Study:

• To demonstrate the efficacy of a Δ-density functional theory (Δ-DFT) approach utilizing atom-centered potentials (ACPs).
• To accurately represent potential energy surfaces (PESs) and calculate vibrational frequencies for HONO and HFCO molecules.
• To establish a computationally inexpensive yet accurate method for molecular property calculations.

Main Methods:

• Employed a Δ-density functional theory (Δ-DFT) approach with atom-centered potentials (ACPs).
• Utilized a limited set of high-accuracy reference energies (CCSD(T)-F12a) to develop ACPs.
• Applied the multiconfigurational time-dependent Hartree (MCTDH) method with ACP-corrected B3LYP/def2-TZVPP potential energy surfaces.

Main Results:

• Achieved low mean absolute errors for PESs of HONO (27.7 cm⁻¹) and HFCO (5.8 cm⁻¹) using as few as 100 reference energies.
• Calculated vibrational frequencies for HONO isomers with mean absolute percent errors (MAPEs) comparable to high-level CCSD(T)-F12a methods (0.8-1.1%).
• Obtained highly accurate vibrational frequencies for HFCO with a MAPE of 0.1%, matching the performance of CCSD(T)-F12a/MCTDH.

Conclusions:

• The atom-centered potential (ACP) approach within Δ-DFT provides a computationally inexpensive and accurate method for PES representation.
• This method successfully models PESs and vibrational frequencies, achieving accuracy comparable to high-level ab initio calculations.
• The ACP approach shows promise as a general protocol for accurate molecular property calculations.