Nonlinear optical property calculations by the long-range-corrected coupled-perturbed Kohn-Sham method

Area of Science:

• Computational Chemistry
• Quantum Chemistry
• Materials Science

Background:

• Density-functional theory (DFT) is widely used for electronic structure calculations.
• Conventional DFT methods often struggle to accurately predict nonlinear optical (NLO) properties.
• Accurate NLO property prediction is crucial for designing advanced materials.

Purpose of the Study:

• To investigate the efficacy of the long-range correction (LC) scheme combined with the coupled-perturbed Kohn-Sham (CPKS) method for calculating NLO properties.
• To assess the performance of the LC-CPKS method for various molecular systems, including push-pull pi-conjugated molecules.
• To determine the role of long-range exchange interactions in DFT-based NLO property calculations.

Main Methods:

• Implementation of the long-range correction (LC) scheme within the coupled-perturbed Kohn-Sham (CPKS) framework.
• Calculation of dipole moments, polarizabilities, and hyperpolarizabilities for representative molecules.
• Application of the LC-CPKS method to push-pull pi-conjugated systems like p-nitroaniline, 4-amino-4'-nitrostilbene, and alpha,omega-nitroaminopolyenes.

Main Results:

• The LC-CPKS method demonstrated significant improvement in calculating NLO properties compared to conventional DFT.
• Calculated hyperpolarizabilities for typical molecules were found to be more accurate.
• Dipole moments, polarizabilities, and hyperpolarizabilities of push-pull systems were accurately reproduced.

Conclusions:

• The long-range correction scheme markedly enhances the accuracy of DFT for predicting nonlinear optical response properties.
• The LC-CPKS method provides a reliable approach for calculating NLO properties of conjugated systems.
• Long-range exchange interactions are vital for accurate DFT-based optical property calculations.