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Potassium-Uracil/Thymine Ring Cleavage Enhancement As Studied In Electron Transfer Experiments And Theoretical Calculations, D Almeida, M.-C. Bacchus-Montabonel, F Ferreira Da Silva, G Garcia, P Limao-Vieira
Potassium-Uracil/Thymine Ring Cleavage Enhancement As Studied In Electron Transfer Experiments And Theoretical Calculations, D Almeida, M.-C. Bacchus-Montabonel, F Ferreira Da Silva, G Garcia, P Limao-Vieira
Faculty of Engineering and Information Sciences - Papers: Part A
We report experimental and theoretical studies on ring cleavage enhancement in collisions of potassium atoms with uracil/thymine in order to further increase the understanding of the complex mechanisms yielding such fragmentation pathways. In these electron transfer processes time-of-flight (TOF) negative ion mass spectra were obtained in the collision energy range 13.5 – 23.0 eV. We note that CNO– is the major ring breaking anion formed and its threshold formation is discussed within the collision energy range studied. Such decomposition process is supported by the first theoretical calculations in order to clarify how DNA/RNA pyrimidine bases fragmentation is enhanced in electron …
Dynamic Of Negative Ions In Potassium-D-Ribose Collisions, D Almeida, F Ferreira Da Silva, G Garcia, P Limao-Vieira
Dynamic Of Negative Ions In Potassium-D-Ribose Collisions, D Almeida, F Ferreira Da Silva, G Garcia, P Limao-Vieira
Faculty of Engineering and Information Sciences - Papers: Part A
We present negative ion formation from collisions of neutral potassium atoms with D-ribose (C5H10O5), the sugar unit in the DNA/RNA molecule. From the negative ion time-of-flight (TOF) mass spectra, OH− is the main fragment detected in the collision range 50–100 eV accounting on average for 50% of the total anion yield. Prominence is also given to the rich fragmentation pattern observed with special attention to O− (16 m/z) formation. These results are in sharp contrast to dissociative electron attachment experiments. The TOF mass spectra assignments show that these channels are also observed, albeit with a much lower relative intensity. Branching …