Potential Functional Embedding Theory at the Correlated Wave Function Level. 2. Error Sources and Performance Tests.

Area of Science:

• Computational Chemistry
• Quantum Mechanics
• Electronic Structure Theory

Background:

• Quantum mechanical embedding theories enable accurate yet cost-efficient calculations by partitioning systems and using varied electronic structure methods.
• Density Functional Embedding Theory (DFET) is fast but non-self-consistent, while Potential Functional Embedding Theory (PFET) offers a rigorous, self-consistent approach.
• Previous work established PFET's viability with mixed Gaussian type orbital/planewave bases.

Purpose of the Study:

• To perform the first correlated wave function (CW)/Density Functional Theory (DFT) calculations using PFET.
• To compare the performance of PFET at the CW/DFT level against DFET and full CW benchmarks.
• To evaluate PFET's ability to correct DFET errors across different interaction types.

Main Methods:

• Implementation and testing of PFET at the correlated wave function (CW)/Density Functional Theory (DFT) level.
• Comparison of CW/DFT PFET results with Density Functional Embedding Theory (DFET) and full CW calculations.
• Introduction of an intermediate DFET/PFET scheme to analyze error correction capabilities.

Main Results:

• PFET at the CW/DFT level demonstrates robust performance across hydrogen bonding, metallic, and ionic interactions.
• The study validates PFET as a more accurate embedding method by showing its capacity to rectify DFET errors.
• The intermediate DFET/PFET scheme highlights PFET's advantages in capturing complex quantum effects.

Conclusions:

• Potential Functional Embedding Theory (PFET) provides a more rigorous and accurate framework for quantum mechanical embedding calculations at the CW/DFT level.
• PFET effectively addresses limitations of DFET, offering improved accuracy for diverse chemical systems.
• This work establishes PFET as a superior embedding theory for optimizing accuracy and computational cost in complex system analysis.