Origin-Independent Dynamic Polarizability Density from Coupled Cluster Response Theory.

Area of Science:

• Quantum Chemistry
• Computational Chemistry
• Molecular Properties

Background:

• Origin-independent dynamic electric dipole polarizability density calculations were previously limited to uncorrelated and Density Functional Theory (DFT) methods.
• Understanding electron correlation's role in polarizability is crucial for accurate molecular modeling.

Purpose of the Study:

• To develop and implement origin-independent dynamic electric dipole polarizability density calculations at the Coupled Cluster Singles and Doubles (CCSD) level.
• To investigate the impact of electron correlation on polarizability density distributions.

Main Methods:

• Implementation of origin-independent dynamic electric dipole polarizability density at the CCSD level of theory.
• Pointwise analysis of polarizability densities for various molecules using Hartree-Fock (HF), CCSD, and B3LYP methods.

Main Results:

• Electron correlation effects on polarizability density are substantially larger than suggested by integrated polarizability values.
• Significant deviations, particularly in internuclear regions, are masked by error compensation during integration.
• Comparison between CCSD and B3LYP shows sign reversals in deviations compared to CCSD and HF, highlighting differences in electron correlation treatment.

Conclusions:

• CCSD level calculations reveal that electron correlation plays a critical role in shaping dynamic electric dipole polarizability density.
• Standard integration methods can obscure important localized deviations in polarizability density, necessitating pointwise analysis.
• The choice of theoretical method (e.g., HF, DFT, CCSD) significantly influences the calculated polarizability density, with notable differences in electron correlation effects.