## 4 Conclusions
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline  & \multicolumn{4}{c}{**A3**} \\ \hline
**Binding Energy (eV)** & **Counts** & **S/N Ratio** & **Spectral Line** & **ID** & **CAS Registry No.** \\ \hline
779.8 & 569,221 & 192 & Ba 3d5/2 & BaO, BaCO\({}_{3}\) & 1304-28-5, 513-77-9 \\
530.4 & 270,703 & 89 & O 1s & -O, -CO\({}_{3}\) & multiple \\
438.0 & 21,532 & 4 & Ca 2s & Ca- & 1305-78-8, 471-34-1 \\
413.5 & 7820 & - & Mo 3p1/2 & Mo\({}_{2}\) & 1317335 \\
401.3 & 6847 & - & Sc 2p3/2 & Sc\({}_{2}\)O\({}_{3}\) & 12060081 \\
399.5 & 9360 & - & Mo 3p3/2 & MoO\({}_{x}\) & 18868434 \\
344.9 & 51,111 & 14 & Ca 2p3/2 & Ca- & 7440-70-2, 471-34-1 \\
288.4 & 45,470 & 12 & C 1s & -COS\({}_{3}\) & multiple \\
284.6 & 54,980 & 15 & C 1s & C (Adv.) & multiple \\
251.4 & 26,598 & 6 & Ba 4s & Ba- & 1304-28-5, 513-77-9 \\
232.0 & 12,743 & - & Mo 3d5/2 & Mo- & 1304-28-5, 513-77-9 \\
177.7 & 71,175 & 214 & Ba 93/2 & Ba- & 1344-28-1 \\
116.3 & 31,455 & 7 & Al 2s & Al- & 1304-28-5, 513-77-9 \\
89.8 & 210,792 & 69 & Ba 4d5/2 & Ba- & 1304-28-5, 513-77-9 \\
63.2 & 5708 & - & Mo 4s & Mo- & 7439-98-7 \\
37.9 & 8519 & - & W 4f5/2 & W- & 1314-35-8 \\
24.8 & 18,925 & 3 & Ca- & 1305-78-8, 471-34-1 \\
13.0 & 22,423 & 4 & Ba 5p3/2 & BaO & 1304-28-5 \\ \hline \hline \end{tabular}
\end{table} 
Table 11: XPS data for point A2. 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{4}{c}{**A2**} \\ \hline
**Binding Energy (eV)** & **Counts** & **S/N Ratio** & **Spectral Line** & **ID** & **CAS Registry No.** \\ \hline
779.8 & 590,068 & 387 & Ba 3d5/2 & BaO, BaCO\({}_{3}\) & 1304-28-5, 513-77-9 \\
530.4 & 283,671 & 185 & O 1s & -O, -CO\({}_{3}\) & multiple \\
438.0 & 14,643 & 8 & Ca 2s & Ca- & 1305-78-8, 471-34-1 \\
413.5 & 2743 & - & Mo 3p1/2 & Mo\({}_{2}\) & 1317335 \\
401.3 & 2342 & - & Sc 2p3/2 & Sc\({}_{2}\)O\({}_{3}\) & 12060081 \\
399.5 & 4563 & 2 & Mo 3p3/2 & MoO\({}_{x}\) & 18868434 \\
344.9 & 37,330 & 23 & Ca 2p3/2 & Ca- & 7440-70-2, 471-34-1 \\
288.4 & 45,696 & 29 & C 1s & -CO\({}_{3}\) & multiple \\
284.6 & 55,070 & 35 & C 1s & C (Adv.) & multiple \\
251.4 & 20,923 & 13 & Ba 4s & Ba- & 1304-28-5, 513-77-9 \\
232.0 & 3786 & - & Mo 3d5/2 & Mo- & 1313-27-5 \\
177.7 & 71,340 & 46 & Ba 4p3/2 & Ba- & 1304-28-5, 513-77-9 \\
116.3 & 25,375 & 16 & Al 2s & Al- & 1344-28-1 \\
89.8 & 257,945 & 168 & Ba 4d5/2 & Ba- & 1304-28-5, 513-77-9 \\
63.2 & 474 & - & Mo 4s & Mo- & 7439-98-7 \\
37.9 & 2587 & - & W 4f5/2 & W- & 1314-35-8 \\
24.8 & 12,712 & 7 & Ca 3p & Ca- & 1305-78-8, 471-34-1 \\
13.0 & 22,443 & 14 & Ba 5p3/2 & BaO & 1304-28-5 \\ \hline \hline \end{tabular}
\end{table} 
Table 12: XPS data for point A3. 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.