Effective Core Potentials for Calculations of Continuum Spectra of Molecules Using the Molecular R-Matrix Method

Area of Science:

• Computational chemistry
• Atomic and molecular physics
• Plasma science

Background:

• Accurate modeling of electron-molecule collisions and photoionization is vital for plasma applications.
• Continuum description in calculations often necessitates numerical continuum functions and molecular integrals.
• Effective Core Potentials (ECPs) offer a computationally efficient way to represent electron-core interactions.

Purpose of the Study:

• To implement effective core potentials (ECPs) within the UKRmol+ computational suite.
• To develop and validate methods for calculating ECP integrals over B-spline-type orbitals.
• To perform benchmark calculations for electron scattering and photoionization relevant to plasma modeling.

Main Methods:

• Derivation of expressions for ECP integrals using momentum-space representation of B-spline-type orbitals.
• Implementation of these expressions into the UKRmol+ software.
• Performing electron collision and photoionization calculations for various molecular targets.

Main Results:

• Successful implementation of ECPs in UKRmol+.
• Calculation of ECP integrals over B-spline-type orbitals.
• Presentation of benchmark calculations for electron scattering with C2H4, Br2, SiBr4, WH, and photoionization of CH3I.

Conclusions:

• The implemented ECP method provides a robust framework for electron-molecule scattering and photoionization studies.
• The calculations demonstrate the utility of the approach for targets relevant to plasma modeling.
• This work enhances the capabilities of UKRmol+ for complex molecular systems.