Excel (Office Open XML) spreadsheets containing the data from Figures 2 and 3. Data from Figure 2 is contained in the sheet labelled 'figure 2': Probability of manipulation (with associated error) as  function  of  radius  from  tip  site  after an injection of−2.1 V and 900 pA for different charge injection durations. Data from Figure 3 is contained in sheet labelled 'figure 3': Half-desorption radius as function of injection duration for−2.1 V  and−1.6 V injections at 900pA.