Electron-molecule collisions with explicit rovibrational resolution at MRCI level and using even tempered basis sets

Area of Science:

• Atomic and Molecular Physics
• Quantum Chemistry
• Spectroscopy

Background:

• Generalized Oscillator Strengths (GOSs) and Differential Cross Sections (DCSs) are key parameters in understanding electron-molecule interactions.
• Previous calculations often neglected the significant contribution of molecular rotation.
• High-resolution experimental data necessitates theoretical methods that account for finer details like vibrational and rotational states.

Purpose of the Study:

• To develop and present a novel computational method for calculating GOSs and DCSs with explicit vibrational and rotational resolution.
• To highlight the importance of incorporating rotational contributions in GOS calculations.
• To achieve theoretical results that are directly comparable to high-resolution experimental measurements.

Main Methods:

• Developed a method for calculating GOSs and DCSs with vibrational and rotational resolution.
• Emphasized the inclusion of rotational contributions, previously overlooked in GOS calculations.
• Utilized even-tempered basis sets for accurate calculation of the electronic scattering amplitude, validated with helium.
• Employed a non-Franck-Condon approach for transitions involving vibrational states.
• Calculated GOSs and DCSs for hydrogen and nitrogen molecules, including specific vibrational and rotational transitions.

Main Results:

• The inclusion of rotational resolution was found to be fundamental for studying phenomena like rotational state interference.
• Calculations for hydrogen and nitrogen molecules yielded GOSs and DCSs with explicit vibrational and rotational transitions.
• The non-Franck-Condon approach improved accuracy for vibrational transitions.
• The computed values demonstrated good agreement with existing experimental data.

Conclusions:

• The presented method provides accurate theoretical GOSs and DCSs with vibrational and rotational resolution.
• Accounting for rotational contributions is essential for detailed molecular studies and matching experimental precision.
• The findings support the use of this method for high-resolution theoretical predictions in electron-molecule scattering research.