Typical cation and anion fragment patterns (insets) of ion stimulated desorption of D-ribose films on Pt substrate induced by (a) , (b) , and (c) ion irradiations. There is a break in the ordinate of the anion spectra in order to show the low yield anions. Note the formation of ion in all cases and the formation of anion in insets of (b) and (c).
Major cation fragments produced by ion irradiation of (a) D-ribose, (b) D-ribose, and (c) 1-D D-ribose films. Each column shows a different segment of mass spectra.
Desorption energy thresholds of major cation and anion fragments produced by (a) and (b) ion irradiations of D-ribose films. All ion yields are normalized to intensity at for ease of comparison. Similar desorption energy thresholds are found for fragments of 2-deoxy-D-ribose films. The yield tail of during ion irradiation is due to contribution of (see text). The experimental uncertainty is about for the obtained threshold values.
Desorption energy thresholds of (a) and (b) ions during and ion irradiations of D-ribose (R) and 2-deoxy-D-ribose (dR) films. All ion yields are normalized to intensity at for ease of comparison.
Mass spectra of anion fragments in between 13 and measured during (a) and (b) ion irradiations of D-ribose at several different energies. The fragment at in (a) is clearly assigned to ion as a result of hydrogen abstraction by ion, which is not seen during ion irradiation. The fragment at in (a) has a contribution from ion, particularly in the low energy range.
(a) Desorption energy thresholds of produced by and ion irradiations of D-ribose films. Similar desorption energy thresholds are found from 2-deoxy-D-ribose films. The lower desorption energy threshold during ion irradiation is due likely to the interaction of an ionic nitrogen atom. Desorption energy threshold of during ion irradiation of 1-D D-ribose film is also shown, which suggests desorption from C–H. (b) Desorption energy thresholds of , , and produced by ion irradiation of 1-D D-ribose films. All ion yields are normalized to intensity at for ease of comparison.
Branching ratios of typical cation fragments originating from specific sites (in %). The ratios are mean values obtained between 30 and ion irradiation of (C5) and 1-D (C1) D-ribose. The numbers in parentheses indicate the number of possible formation channels from that particular site(s) (Ref. 13).
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