pyHRSOA and pyTHSOA: Postprocessing Codes for the Computation of Second and Third-Order Scattering Optical Activities

Area of Science:

• Computational chemistry
• Spectroscopy
• Chiroptics

Background:

• Nonlinear chiroptical techniques like hyper-Rayleigh scattering optical activity (HRS-OA) and third-harmonic scattering optical activity (THS-OA) rely on the circular differential scattering ratio.
• Calculating this ratio involves complex molecular invariants and hyperpolarizabilities, complicating computational implementation.

Purpose of the Study:

• To present pyHRSOA and pyTHSOA, user-friendly Python postprocessing codes.
• To simplify the computation of the circular differential scattering ratio for HRS-OA and THS-OA spectroscopies.

Main Methods:

• Developed two Python codes, pyHRSOA and pyTHSOA, as black-box tools.
• Utilized DALTON quantum chemistry software for calculating hyperpolarizabilities from response functions.
• Focused on simplifying the complex expressions for chiral and achiral contributions to scattered intensities.

Main Results:

• Successfully created postprocessing codes that streamline the computation of the circular differential scattering ratio.
• The codes handle the complexity of 30 (for HRS-OA) and 46 (for THS-OA) molecular invariants.
• Provided accessible source code for researchers.

Conclusions:

• pyHRSOA and pyTHSOA significantly ease the computational burden for HRS-OA and THS-OA spectroscopy.
• These tools enable broader application of novel nonlinear chiroptical techniques.
• Facilitated research in molecular chirality and optical properties.