## 4 Conclusions
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline  & & & & & \\ \hline
**Binding Energy (eV)** & **Counts** & **S/N Ratio** & **Spectral Line** & **ID** & **CAS Registry No.** \\ \hline
779.8 & 1,331,531 & 478 & Ba 3d5/2 & BaO, BaCO\({}_{3}\) & 1304-28-5, 513-77-9 \\
530.4 & 498,640 & 176 & O 1s & -O, -CO\({}_{3}\) & multiple \\
438.0 & 20,958 & 2 & Ca 2s & Ca- & 1305-78-8, 471-34-1 \\
413.5 & 25,081 & 2 & Mo 3p1/2 & MoS\({}_{2}\) & 1317335 \\
401.3 & 15,240 & - & Sc 2p3/2 & Sc\({}_{2}\)O\({}_{3}\) & 12060081 \\
399.5 & 29,659 & 5 & Mo 3p3/2 & MoO\({}_{x}\) & 18868434 \\
344.9 & 22,964 & 3 & Ca 2p3/2 & Ca- & 7440-70-2, 471-34-1 \\
288.4 & 101,072 & 31 & C 1s & -CO\({}_{3}\) & multiple \\
284.6 & 176,840 & 59 & C 1s & C (Adv.) & multiple \\
251.4 & 70,249 & 20 & Ba 4s & Ba- & 1304-28-5, 513-77-9 \\
232.0 & 68,106 & 19 & Mo 3d5/2 & Mo- & 1313-27-5 \\
177.7 & 181,507 & 61 & Ba 4p3/2 & Ba- & 1304-28-5, 513-77-9 \\
116.3 & 69,055 & 20 & Al 2s & Al- & 1344-28-1 \\
89.8 & 469,156 & 165 & Ba 4d5/2 & Ba- & 1304-28-5, 513-77-9 \\
63.2 & 10,215 & - & Mo 4s & Mo- & 7439-98-7 \\
37.9 & 19,843 & 2 & W 4f5/2 & W- & 1314-35-8 \\
24.8 & 22,290 & 3 & Ca 3p & Ca- & 1305-78-8, 471-34-1 \\
13.0 & 53,831 & 14 & Ba 5p3/2 & BaO & 1304-28-5 \\ \hline \hline \end{tabular}
\end{table} 
Table 10: XPS data for point A1. 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  & & & & & \\ \hline
**Binding Energy (eV)** & **Counts** & **S/N Ratio** & **Spectral Line** & **ID** & **CAS Registry No.** \\ \hline
779.8 & 8815 & 2 & Ba 3d5/2 & BaO, BaCO\({}_{3}\) & 1304-28-5, 513-77-9 \\
530.4 & 557,050 & 287 & O 1s & -O, -CO\({}_{3}\) & multiple \\
401.3 & 3551 & - & Sc 2p3/2 & Sc\({}_{2}\)O\({}_{3}\) & 12060081 \\
379.2 & 10,942 & 3 & K 2s & K- & 7440-09-7 \\
351.1 & 19,379 & 4 & Ca 2p1/2 & CaCO\({}_{3}\) & 1304-28-5, 513-77-9 \\
306.8 & 19,842 & 8 & Mg KLL & Mg- & Ref. [18] \\
293.8 & 28,937 & 12 & K 1s & K- & 7440-09-7 \\
288.4 & 27,402 & 12 & C 1s & -CO\({}_{3}\) & multiple \\
284.6 & 183,564 & 93 & C 1s & C (Adv.) & multiple \\
251.4 & 5120 & - & Ba 4s & Ba- & 1304-28-5, 513-77-9 \\
177.7 & 20,551 & 8 & Ba 4p3/2 & Ba- & 1304-28-5, 513-77-9 \\
153.8 & 100,824 & 50 & Si 2s & SiO\({}_{2}\) & 7631-86-9 \\
119.0 & 19,531 & 8 & Al 2s & Al- & 1344-28-1 \\
102.8 & 118,811 & 59 & Si 2p & SiO\({}_{2}\) & 7631-86-9 \\
89.8 & 6215 & - & Ba 4d5/2 & BaO, BaCO\({}_{3}\) & 1304-28-5, 513-77-9 \\
74.3 & 9871 & 2 & Al 2p3/2 & Al\({}_{2}\)O\({}_{3}\) & 1344-28-1 \\
49.9 & 7944 & 1 & Mg 2p & Mg- & 7439-95-4 \\
28.6 & 8793 & 2 & Ba 5s & Ba- & 1304-28-5, 513-77-9 \\
24.8 & 27,283 & 12 & Ca 3p & Ca- & 1305-78-8, 471-34-1 \\
13.0 & 7479 & - & Ba 5p3/2 & BaO & 1304-28-5 \\ \hline \hline \end{tabular}
\end{table} 
Table 9: XPS data for point A9. 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.