# A Theoretical Study on the Electronic Excitation of the Pyridine Molecule by Electron Impact

## TL;DR

This paper studies how electrons excite pyridine molecules, calculating cross sections for various energy levels up to 50 eV.

## Contribution

The study introduces a detailed theoretical model for electron-pyridine collisions with up to 301 coupled states.

## Key findings

- Computed elastic cross sections align well with experimental data and identify π* resonance positions.
- Excitation cross sections to low-lying states are highly sensitive to opening thresholds.
- The results show higher magnitudes than previous theoretical predictions but maintain reasonable trend agreement.

## Abstract

In this work, we present a theoretical investigation
of electron
collisions by the pyridine molecule. Elastic cross sections and electronic
inelastic cross sections involving the transitions from the ground
state to the 13
A
1, 13
B
2, 23
A
1, 13
B
1, 13
A
2, 11
B
2, 11
B
1, and 11
A
2 excited states of pyridine are reported
in the energy range from 0 to 50 eV. The scattering amplitudes were
obtained using the Schwinger multichannel method, and the effects
of multichannel coupling were accounted for by means of the minimal
orbital basis for single-configuration interactions strategy. This
strategy gives rise to an up to 301-states level of channel coupling
calculation and enables us to evaluate the influence of flux stealing
due to competition of energetically accessible channels upon the magnitude
of the cross sections. Our computed elastic cross sections are in
very good agreement with existing experimental data and provide positions
for the three π* resonances, which are consistent with previous
assignments. The present results involving the transitions from the
ground state to the lowest-lying excited states of the pyridine are
shown to be very sensitive to the influence of opening thresholds.
Compared with the only theoretical result reported in the literature
so far, our excitation cross sections present a higher magnitude.
Despite this fact, for almost all transitions considered, the agreement
in terms of general trends is reasonable and quite encouraging.