Nanoscale Effects of Radiation (UV, X-ray & gamma) on Calcite Surfaces: Implications for its Mechanical and Physico-Chemical Properties

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1 Nanoscale Effects of Radiation (UV, X-ray & gamma) on Calcite Surfaces: Implications for its Mechanical and Physico-Chemical Properties Z. Kabacińska 1, L. Yate 2, M. Wencka 3, R. Krzyminiewski 1, K. Tadyszak 2,4, E. Coy 4* 1 Medical Physics Division, Faculty of Physics, Adam Mickiewicz University, Umultowska 85, Poznań , Poland 2 CIC biomagune, Paseo Miramon 182, 20009, San Sebastian, Spain 3 Department of Solid State Radiospectroscopy, Institute of Molecular Physics, Polish Academy of Sciences, Smoluchowskiego 17, , Poznań, Poland 4 NanoBioMedical Centre, Adam Mickiewicz University, Umultowska 85, Poznan, Poland *Corresponding Author: coyeme@amu.edu.pl Table of contents: Supplementary Figures: Figure S1: XRD pattern Figure S2: Images of calcite surface after UV irradiation Figure S3: Atomic force micrographs of the surfaces Figure S4: Concentration of defects - Figure S5: EPR growth curves for SO 3 Figure S6: XPS spectra of Ca 2p Figure S7: XPS Auger spectra of Ca Figure S8: XPS spectra of O 1s Figure S9: H/E ratio and the total concentration of defects p(s2) p(s3) p(s4) p(s5) p(s6) p(s7) p(s8) p(s9) p(s10) Supplementary Tables: Table S1: ICP-MS analysis Table S2: List of paramagnetic centres observed in EPR Table S3: Binding energies of C, Ca and O p(s11) p(s12) p(s13) S1

2 θ [ o ] Figure S1: XRD pattern single crystal calcite (104) (top panel in blue) and of the powdered single crystal (mid panel in black) and the corresponding reference pattern ICCD PDF: (bottom panel in red). S2

3 Figure S2: Images of calcite single crystal (104) surface collected by optical microscope, showing the reduction of the number of cracks after UV irradiation. S3

4 Figure S3: Atomic force micrographs of surfaces before and after irradiation. Rq shows the root mean square value (roughness) of the surfaces. S4

5 Figure S4: Concentration of radiation defects in powdered calcite grinded before and after gamma irradiation (10% uncertainty). S5

6 Figure S5 Growth curves (spin concentration vs dose or time of irradiation) for radiation induced axial SO - 3 defect measured with EPR in powdered calcite sample. Exponential functions following the equation given in the text were fitted to the experimental data for gamma and X-rays. Uncertainty of spin concentration was estimated as 10%. S6

7 Figure S6: XPS spectra of Ca 2p peak after last irradiation using UV, X-rays and gamma. S7

8 Figure S7: a) XPS calculated Auger parameter of Ca for the samples, b) values for all the irradiated crystals. S8

9 Figure S8: XPS spectra of O 1s peak after last irradiation using UV, X-rays and gamma. S9

10 Figure S9: H/E ratio calculated from nanoindentation data and the total concentration of defects obtained from EPR growth curves, for the sample irradiated with a) UV, b) X-ray, c) gamma radiation. The surface defect caused by grinding was not included in total spin concentration. S10

11 Table S1: Concentration of impurities (in wt.%) in the calcite sample obtained from ICP- MS and the resulting concentration of CaCO 3 calculated on that basis. Concentration (wt.%) Na Mg Al Si P S K Mn Fe Ni Zn CaCO S11

12 Table S2: Paramagnetic centers in calcite samples observed with EPR spectrometry. The G-factor values (± ) and linewidths were obtained from computer simulations. All the signals except the surface defect were simulated using Gaussian curves. Paramagnetic centre CO 2 - orthorhombic CO 2 - orthorhombic II Irradiation g-factor value linewidth (mt) γ, UV, X UV g x = g y = g z = g x = g y = g z = CO 2 - isotropic γ, UV, X g = CO 3 - orthorhombic SO 3 - axial γ, UV, X γ, X g x = g y = g z = g x = g y = g z = SO 2 - isotropic before, γ, UV, X g = surface defect 0 before g = surface defect γ, UV, X g x = g y = g z = Lorentzian curve L x = 0.05 L y = 0.05 L z = 0.07 organic radical before, γ, UV, X g = Fe 3+ before, γ, UV, X g = S12

13 Table S3: Binding energies for CaCO 3 elements. Element/ Sample Transition natural UV X gamma Bond Reference Ca 2p 1/ a, e Ca 2p 3/ Ca-CO 3 a, b, c, e CO 3 (carbonate) a, b, c, e C=O e C 1s C-O e C-C, C-H ( adventitious carbon ) a, d, e O 1s O-H, C-O a, b, c, e Ca-O e a Stipp & Hochella b Baer et al c Baer et al d Barr & Seal e Moulder et al S13

14 References: (1) Stipp, S. L.; Hochella, M. F. Structure and Bonding Environments at the Calcite Surface as Observed with X-Ray Photoelectron Spectroscopy (XPS) and Low Energy Electron Diffraction (LEED). Geochim. Cosmochim. Acta 1991, 55, (2) Baer, D. R. Comparison Spectra for Calcite by XPS. Surf. Sci. Spectra 1992, 1, 80. (3) Baer, D. R.; Blanchard, D. L. Studies of the Calcite Cleavage Surface for Comparison with Calculation. Appl. Surf. Sci. 1993, 72, (4) Barr, T. L.; Seal, S. Nature of the Use of Adventitious Carbon as a Binding Energy Standard. J. Vac. Sci. Technol. A Vacuum, Surfaces, Film. 1995, 13, (5) Moulder, J. F.; Stickle, W. F.; Sobol, P. E.; Bomben, K. D. Handbook of X-Ray Photoelectron Spectroscopy; Chastain, J.; King Jr., R.., Eds.; 3rd ed.; Physical Electronics, Inc., S14