Dynamic of negative ions in potassium-D-ribose collisions.
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 ratios of the most abundant fragment anions as a function of the collision energy are obtained, allowing to establish a rationale on the collision dynamics.
Laboratório de Colisões Atómicas e Moleculares, CEFITEC, Departamento de Física, Faculdade de Cie^ncias e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal.
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Almeida
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Ferreira da Silva
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García
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Limão-Vieira
D000838:Anions / Q000737:chemistry*; D004247:DNA / Q000737:chemistry*; D013058:Mass Spectrometry; D011188:Potassium / Q000737:chemistry*; D012313:RNA / Q000737:chemistry*; D012266:Ribose / Q000737:chemistry*
D000838:Anions; D012313:RNA; D012266:Ribose; D004247:DNA; D011188:Potassium