A reduced cost four-component relativistic coupled cluster method based on natural spinors

Area of Science:

• Quantum Chemistry
• Computational Chemistry
• Relativistic Quantum Mechanics

Background:

• Coupled cluster methods are essential for accurate electronic structure calculations.
• Four-component relativistic methods are necessary for heavy elements.
• Standard methods face challenges with computational cost and convergence.

Purpose of the Study:

• To introduce a reduced-cost four-component relativistic coupled cluster method using frozen natural spinors.
• To improve the efficiency and accuracy of electronic structure calculations for relativistic systems.

Main Methods:

• Utilizing frozen natural spinors derived from relativistic second-order Møller-Plesset calculations.
• Implementing a four-component Dirac-Coulomb Hamiltonian.
• Applying perturbative corrections to enhance convergence.

Main Results:

• Frozen natural spinors basis shows faster correlation energy convergence compared to canonical spinors.
• Perturbative corrections smooth property convergence and reduce truncation errors.
• The method offers controllable accuracy via a single threshold, functioning as a black box.

Conclusions:

• The frozen natural spinor based coupled cluster method provides a computationally efficient and accurate approach for relativistic electronic structure calculations.
• This method simplifies the process and improves the reliability of results for complex molecular systems.