Tuned Range-Separated Density Functional Theory and Dyson Orbital Formalism for Photoelectron Spectra

Area of Science:

• Computational chemistry
• Molecular spectroscopy
• Quantum chemistry

Background:

• Photoelectron spectroscopy is crucial for analyzing molecular systems.
• Accurate interpretation of experimental data necessitates reliable theoretical modeling.
• Existing theoretical methods may have limitations in predicting ionization properties.

Purpose of the Study:

• To present a robust theoretical protocol for predicting ionization energies and intensities.
• To improve the accuracy of theoretical modeling in photoelectron spectroscopy.
• To provide a reliable method for analyzing structural and dynamical changes in molecules.

Main Methods:

• Utilizing linear-response time-dependent density functional theory (LR-TDDFT).
• Employing the Dyson orbital formalism.
• Implementing optimally tuned range-separated hybrid density functionals.

Main Results:

• The protocol accurately predicts ionization energies and intensities for various gas-phase molecules.
• Optimally tuned range-separated hybrid functionals improve predictions for both frontier and deeper orbitals.
• The method demonstrates good agreement with experimental data across different molecular classes.

Conclusions:

• The presented protocol offers a reliable approach for theoretical modeling in photoelectron spectroscopy.
• The study highlights the importance of density functional choice and parameter tuning.
• Potential sources of inaccuracy, such as parameter ambiguities and spin contamination, were identified and discussed.