## 4 Conclusions
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline  & \multicolumn{4}{c}{**G5**} \\ \hline
**Binding Energy (eV)** & **Counts** & **S/N Ratio** & **Spectral Line** & **ID** & **CAS Registry No.** \\ \hline
779.8 & 210,360 & 32 & Ba 3d5/2 & BaO, BaCO\({}_{3}\) & 1304-28-5, 513-77-9 \\
530.4 & 466,506 & 72 & O 1s & -O, -CO\({}_{3}\) & multiple \\
401.3 & 4487 & - & Sc 2p3/2 & Sc\({}_{2}\)O\({}_{3}\) & 12060081 \\
379.2 & 5591 & - & K 2s & K- & 7440-09-7 \\
351.1 & 36,380 & 5 & Ca 2p1/2 & CaCO\({}_{3}\) & 1304-28-5, 513-77-9 \\
306.8 & 127,826 & 19 & Mg KLL & Mg- & Ref. [18] \\
293.8 & 19,492 & 2 & K 1s & K- & 7440-09-7 \\
288.4 & 55,283 & 8 & C 1s & -CO\({}_{3}\) & multiple \\
284.6 & 258,716 & 40 & C 1s & C (Adv.) & multiple \\
251.4 & 14,716 & - & Ba 4s & Ba- & 1304-28-5, 513-77-9 \\
177.7 & 39,347 & 5 & Ba 4p3/2 & Ba- & 1304-28-5, 513-77-9 \\
153.8 & 45,632 & 6 & Si 2s & SiO\({}_{2}\) & 7631-86-9 \\
119.0 & 21,454 & 2 & Al 2s & Al- & 1344-28-1 \\
102.8 & 53,776 & 7 & Si 2p & SiO\({}_{2}\) & 7631-86-9 \\
89.8 & 84,035 & 12 & Ba 4d5/2 & BaO, BaCO\({}_{3}\) & 1304-28-5, 513-77-9 \\
74.3 & 16,239 & - & Al 2p3/2 & Al\({}_{2}\)O\({}_{3}\) & 1344-28-1 \\
49.9 & 23,692 & 3 & Mg 2p & Mg- & 7439-95-4 \\
28.6 & 14,458 & - & Ba 5s & Ba- & 1304-28-5, 513-77-9 \\
24.8 & 22,825 & 2 & Ca 3p & Ca- & 1305-78-8, 471-34-1 \\
13.0 & 13,960 & - & Ba 5p3/2 & BaO & 1304-28-5 \\ \hline \hline \end{tabular}
\end{table} 
Table 5: XPS data for point G5. Binding energy and counts taken from the overview spectra. S/N ratios were computed manually. A “-” indicates an S/N ratio below 1.5, implying signal indistinguishable from background. Spectral line and ID were taken from the NIST XPS Database [22]. See text for details. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline  & & \multicolumn{3}{c}{**G7**} \\ \hline
**Binding Energy (eV)** & **Counts** & **S/N Ratio** & **Spectral Line** & **ID** & **CAS Registry No.** \\ \hline
779.8 & 69,591 & 29 & Ba 3d5/2 & BaO, BaCO\({}_{3}\) & 1304-28-5, 513-77-9 \\
530.4 & 564,110 & 252 & O 1s & -O, -CO\({}_{3}\) & multiple \\
401.3 & 7983 & - & Sc 2p3/2 & Sc\({}_{2}\)O\({}_{3}\) & 12060081 \\
379.2 & 7063 & - & K 2s & K- & 7440-09-7 \\
351.1 & 5930 & - & Ca 2p1/2 & CaCO\({}_{3}\) & 1304-28-5, 513-77-9 \\
306.8 & 15,260 & 4 & Mg KLL & Mg- & Ref. [18] \\
293.8 & 18,593 & 6 & K 1s & K- & 7440-09-7 \\
288.4 & 26,542 & 10 & C 1s & -CO\({}_{3}\) & multiple \\
284.6 & 87,381 & 37 & C 1s & C (Adv.) & multiple \\
251.4 & 5031 & - & Ba 4s & Ba- & 1304-28-5, 513-77-9 \\
177.7 & 20,833 & 7 & Ba 4p3/2 & Ba- & 1304-28-5, 513-77-9 \\
153.8 & 94,998 & 40 & Si 2s & SiO\({}_{2}\) & 7631-86-9 \\
119.0 & 17,314 & 5 & Al 2s & Al- & 1344-28-1 \\
102.8 & 113,444 & 49 & Si 2p & SiO\({}_{2}\) & 7631-86-9 \\
89.8 & 20,805 & 7 & Ba 4d5/2 & BaO, BaCO\({}_{3}\) & 1304-28-5, 513-77-9 \\
74.3 & 9327 & 2 & Al 2p3/2 & Al\({}_{2}\)O\({}_{3}\) & 1344-28-1 \\
49.9 & 7379 & - & Mg 2p & Mg- & 7439-95-4 \\
28.6 & 16,843 & 5 & Ba 5s & Ba- & 1304-28-5, 513-77-9 \\
24.8 & 25,318 & 9 & Ca 3p & Ca- & 1305-78-8, 471-34-1 \\
13.0 & 7144 & - & Ba 5p3/2 & BaO & 1304-28-5 \\ \hline \hline \end{tabular}
\end{table} 
Table 7: XPS data for point G7. Binding energy and counts taken from the overview spectra. S/N ratios were computed manually. A “-” indicates an S/N ratio below 1.5, implying signal indistinguishable from background. Spectral line and ID were taken from the NIST XPS Database [22]. See text for details.