Calculation of photoionization differential cross sections using complex Gauss-type orbitals

Area of Science:

• Quantum Chemistry
• Theoretical Chemistry
• Molecular Spectroscopy

Background:

• Accurate theoretical calculations are crucial for real-time imaging of chemical reactions.
• Photoelectron angular distributions (PADs) provide insights into molecular dynamics.

Purpose of the Study:

• To demonstrate the accurate calculation of PADs and photoionization cross sections using complex Gauss-type orbital (cGTO) basis functions.
• To present a method applicable to various molecules and integrable with quantum chemistry techniques.

Main Methods:

• Utilized the two-potential formula to represent transition dipole moments.
• Employed a complex basis function method with a mix of cGTOs and real GTOs for continuum and bound orbitals.
• Optimized cGTO complex orbital exponents by fitting to Coulomb functions.

Main Results:

• Successfully calculated asymmetry parameters and molecular-frame PADs for H2+ and H2.
• Demonstrated the accuracy of the cGTO basis set for theoretical calculations.
• Investigated the impact of static exchange and random phase approximations on H2 calculations.

Conclusions:

• The cGTO basis function method enables accurate theoretical calculations of PADs and photoionization cross sections.
• This approach is versatile, applicable to diverse molecules, and compatible with electron correlation methods.
• The method provides a powerful tool for real-time chemical reaction dynamics studies.