Using Electronic Energy Derivative Information in Automated Potential Energy Surface Construction for Vibrational...

Area of Science:

• Computational Chemistry
• Theoretical Chemistry
• Quantum Chemistry

Background:

• Accurate potential energy surfaces (PESs) are crucial for anharmonic vibrational calculations.
• High dimensionality and scaling issues of coupled PESs make their construction computationally intensive.
• Developing efficient, black-box protocols for PES construction is a significant challenge.

Purpose of the Study:

• To develop and present an integrated computational machinery for efficient PES construction.
• To introduce and evaluate two novel methods, ADGA[2gx3M] and ADGA[2hx3M], for PES generation.
• To assess the accuracy and computational efficiency of these methods in vibrational coupled cluster (VCC) calculations.

Main Methods:

• Adaptive Density-Guided Approach (ADGA) for selecting evaluation points.
• Modified Shepard (MS) interpolation and extrapolation using derivative information (gradients and Hessians).
• Development of ADGA[2gx3M] (two-mode couplings) and ADGA[2hx3M] (three-mode couplings) protocols.

Main Results:

• The developed machinery provides efficient and accurate PES construction protocols.
• ADGA[2gx3M] and ADGA[2hx3M] demonstrate good accuracy and computational efficiency for modest-sized grids.
• Vibrational coupled cluster calculations on benchmark molecules (CHFClBr, CH2NH, C3H3NO) show the effectiveness of the generated PESs.

Conclusions:

• The integrated approach offers a powerful tool for generating PESs for vibrational analysis.
• The ADGA[2gx3M] and ADGA[2hx3M] methods represent a significant advancement in computational efficiency and accuracy for PES construction.
• The study successfully validates the developed methods on relevant molecular systems, paving the way for accurate anharmonic vibrational calculations.