Publication . Almeida, D.; Ferreira da Silva, F.; Garcia, G.; Limão-Vieira, P.; CeFITec – Centro de Física e Investigação Tecnológica; DF – Departamento de Física; AIP - American Institute of Physics
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- (16m/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. (C) 2013 AIP Publishing LLC.
