Shape and energy consistent pseudopotentials for correlated electron systems

Area of Science:

• Computational Chemistry
• Quantum Chemistry
• Electronic Structure Theory

Background:

• Pseudopotentials are crucial for simplifying correlated-electron calculations.
• Existing pseudopotential methods often introduce significant errors.
• The need for accurate and computationally efficient pseudopotentials is persistent in electronic structure research.

Purpose of the Study:

• To develop a novel method for generating energy consistent correlated electron pseudopotentials (eCEPPs).
• To combine shape and energy consistency paradigms for improved pseudopotential accuracy.
• To construct and validate eCEPPs for a range of atomic elements.

Main Methods:

• Developed a method combining shape and energy consistency for pseudopotential generation.
• Defined consistency in terms of correlated-electron wave-functions.
• Constructed eCEPPs for H, Li-F, Sc-Fe, and Cu.
• Validated accuracy using coupled cluster singles, doubles, and triples (CCSD(T)) calculations.
• Optimized Gaussian basis sets for use with the new pseudopotentials.

Main Results:

• eCEPPs demonstrate significant improvements in optimized molecular geometries.
• Dissociation energies calculated with eCEPPs show an order-of-magnitude reduction in error compared to Hartree-Fock-based pseudopotentials.
• The accuracy of eCEPPs was validated against all-electron results.
• Errors inherent in eCEPPs were analyzed and compared to common pseudopotential approximations.

Conclusions:

• The developed eCEPPs represent a substantial advancement for accurate correlated-electron calculations.
• These pseudopotentials offer superior performance for molecular geometry optimization and dissociation energy calculations.
• eCEPPs provide a more reliable and accurate alternative to existing pseudopotential methods in computational chemistry.