Theoretical Investigation of Electron Impact Scattering on Imidazole

Abstract

This study presents the results of electron scattering calculations on a biologically important molecule, imidazole, using the UK molecular R-matrix method. The R-matrix calculations are performed using SE, SEP, and CC models, and the resonance detected in the present SEP model is found to be in better agreement with available experimental data than previous theoretical data. The study also reports an inelastic scattering cross section, which comprises dissociative electron attachment (DEA), excitation, and ionization cross section, for the first time. The total scattering cross sections are also reported for the first time. We confirm the presence of the two well-known π* shape resonances predicted earlier experimentally. Due to the scarcity of total scattering cross section (TCS) data for imidazole, we have compared the TCS of imidazole with its isoelectronic target isoxazole and drawn important conclusions. A comparison among the resonances of imidazole with those of isoxazole helps us to conclude that electron attachment to π* molecular orbitals is a general feature displayed by these five-membered heterocyclic compounds. The comprehensive electron scattering studies presented in this work are expected to provide a deeper understanding of electron-induced biochemical processes and fill gaps in the available data. Furthermore, this study is anticipated to inspire further investigations on imidazole and other five-membered heterocyclic ring molecules, which have significant applications in medicine.

Isomeric effects on the electron impact scattering for selected five membered heterocyclic ring molecules

“…Figure 6 presents the symmetry component contributions to the total elastic scattering cross-section for imidazole and pyrazole molecules. The elastic cross-sectional data for the imidazole molecule is already published in [10]. However, the idea behind comparison here is to see the clear isomeric effect on the elastic cross-sectional data.…”

“…In our previous investigations, we undertook a comprehensive low energy electron scattering study on different five membered ring molecules (FMRMs) specifically, isoxazole [8], thiazole [9], and imidazole [10]. In this paper, we focus on their isomers namely oxazole, isothiazole and pyrazole respectively.…”

Interaction of low-energy electrons with radiosensitizers

“…Imidazole loses hydrogen via shape resonances in 1.5–4 eV range, 176,178 presumably upon electron attachment to the LUMO and LUMO+2 orbitals. 177,179,180 In isoxazole additionally, O–N bond can be cleaved at energies as low as 1.5 eV leading to the ring opening. 181,182 At higher energies, core excited resonances can be identified in the 6–11 eV range also leading to the N–O bond cleavages and ring opening in imidazole 176 or isoxazole.…”

Low energy electron scattering cross sections of cyanotriacetylene (HC7N) based on ab-initio R-matrix method

“…The ab-initio R-matrix method Present scattering calculations were performed using the Quantemol-EC [24] software which utilizes the UK molecular R-matrix code. The R-matrix theory has been described in detail elsewhere [25][26][27][28], and therefore we give just a brief overview here. This approach involves division of configuration space for electron-molecular collision problems into inner and outer regions to mitigate complexity.…”