Banca de DEFESA: MARIANA BEZERRA MANGABEIRA SIMÕES DE MEDEIROS

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : MARIANA BEZERRA MANGABEIRA SIMÕES DE MEDEIROS
DATE: 22/09/2023
TIME: 14:30
LOCAL: Plataforma da conferência WEB - RNP
TITLE:

Computational Determination of the Ionization Cross Section and Asymmetry Parameter of Heterocyclic Organic Molecules

KEY WORDS:

Photoionization, Cross-section, Asymmetry Parameter, Heterocyclic Molecules.

PAGES: 92
BIG AREA: Ciências Exatas e da Terra
AREA: Física
SUMMARY:

In this work, we examined the process of molecular photoionization, which occurs when
the incident photon has enough energy to ionize the molecule. Specifically, we conducted
a theoretical study of the photoionization of the heterocyclic molecules Pyrrole (C4H5N)
and Furan (C4H4O), using the Restricted Hartree-Fock (RHF) and Density Functional
Theory (DFT) methods to describe the isolated target. Particularly, we determined the
photoionization cross-sections and the asymmetry parameter. The results were obtained

using the computational package epolyScat-E. For both molecules, we performed calcu-
lations of the photoionization cross-sections in length and velocity approximation, both

with and without the inclusion of the polarization effect (Perdew and Zunger potential -
PZ), in the energy range between 8.2 and 50 eV. From the obtained results, we observed
that the performance of the two electronic structure calculation methods used in this
work was similar. In general, the cross-sections of the analyzed molecules have common
characteristics, in length form they differ quantitatively from the curves in velocity form.
When we included the polarization potential, the difference between the two forms of the
cross-section was reduced, and there was a shift of the resonance features of the curves in

lower energies. We note that the inclusion of polarization via the PZ potential did not sig-
nificantly improve our results when compared to the experimental data; the cross-sections

in velocity form without polarization were in better agreement with the experimental

results. Regarding the asymmetry parameter, we observed differences between the cur-
ves with and without polarization, but there were no significant differences between the

length and velocity curves. Additionally, concerning the resonance positions, the asym-
metry parameter curve generally has a minimum, while the photoionization cross-section

has a maximum. This work contributes to the research of accurate theoretical methods
that provide reliable values of quantities associated with the photoionization process and
can guide the search for experimental results involving target molecules for which such
data is scarce.

COMMITTEE MEMBERS:
Externo à Instituição - GABRIEL LUIZ CRUZ DE SOUZA - UFMT
Externa à Instituição - ROMARLY FERNANDES DA COSTA - UnB
Presidente - 1194645 - FREDERICO VASCONCELOS PRUDENTE
Externo à Instituição - MANOEL GUSTAVO PETRUCELLI HOMEM - UFSCAR
Interno - 2422135 - RICARDO DOS REIS TEIXEIRA MARINHO