Bound Electron Enhanced Radiosensitisation of Nimorazole upon Charge Transfer

Sarvesh Kumar, Islem Ben Chouikha, Boutheïna Kerkeni, Gustavo García, Paulo Limão-Vieira

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)
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This novel work reports nimorazole (NIMO) radiosensitizer reduction upon electron transfer in collisions with neutral potassium (K) atoms in the lab frame energy range of 10-400 eV. The negative ions formed in this energy range were time-of-flight mass analyzed and branching ratios were obtained. Assignment of different anions showed that more than 80% was due to the formation of the non-dissociated parent anion NIMO#~ at 226 u and nitrogen dioxide anion NC2- at 46 u. The rich fragmentation pattern revealed that significant collision induced the decomposition of the 4-nitroimidazole ring, as well as other complex internal reactions within the temporary negative ion formed after electron transfer to neutral NIMO. Other fragment anions were only responsible for less than 20% of the total ion yield. Additional information on the electronic state spectroscopy of nimorazole was obtained by recording a K+ energy loss spectrum in the forward scattering direction (9 « 0°), allowing us to determine the most accessible electronic states within the temporary negative ion. Quantum chemical calculations on the electronic structure of NIMO in the presence of a potassium atom were performed to help assign the most significant lowest unoccupied molecular orbitals participating in the collision process. Electron transfer was shown to be a relevant process for nimorazole radiosensitisation through efficient and prevalent non-dissociated parent anion formation.

Original languageEnglish
Article number4134
Number of pages16
Issue number13
Publication statusPublished - 28 Jun 2022


  • nimorazole
  • electron transfer
  • radiosensitizer
  • TOF mass spectrum
  • energy loss spectrum


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