## 3 Results and Discussion
### XPS Spectra and XPS Characteristics  
Figure 6 shows XPS spectra before and after the TPPE measurement for copper sheets subjected to only ultrasonic cleaning for 5 min in the liquids and mechanical abrasion for different periods of 5 min, 10 min, and 30 min in the liquids and ambient air: H\({}_{2}\)O, CH\({}_{3}\)OH, C\({}_{2}\)H\({}_{5}\)OH, (CH\({}_{3}\))\({}_{2}\)CHOH, C\({}_{3}\)H\({}_{7}\)OH, and ambient air. We paid attention to three points, Cu\({}_{\rm LMM}\), O1s, and the shake-up satellite structure 6-10 eV above the main Cu2p peak. Figure 5: Dependence of \(N_{\rm T}\) vs. temperature (TPPE plot) for copper samples subjected to 10-minute abrasion (sample A, **above**) and ultrasonic cleaning alone (sample C, **below**) on the liquids and air: (a) H\({}_{2}\)O, (b) CH\({}_{3}\)OH, (c) C\({}_{2}\)H\({}_{5}\)OH, (d) (CH\({}_{3}\))\({}_{2}\)CHOH, (e) C\({}_{3}\)H\({}_{7}\)OH, and (f) ambient air. Figure 6: _Cont._  
The XPS spectra and characteristics are summarized as follows [26]. Figure 6: [Samples A and C] XPS spectra before and after TPPE measurement for copper sheets subjected to only ultrasonic cleaning in liquids and mechanical abrasion by a steel screw for certain periods in liquids and ambient air. Liquids and air: H\({}_{2}\)O, CH\({}_{3}\)OH, C\({}_{2}\)H\({}_{5}\)OH, (CH\({}_{3}\))\({}_{2}\)CHOH, C\({}_{3}\)H\({}_{7}\)OH, and ambient air; (a) cleaned sample: after only ultrasonic cleaning for 5 min; (b–d) abraded samples: (b) 5-min abrasion; (c) 10-min abrasion; (d) 30-min abrasion. It should be noted that the intensities of each spectrum are represented by the unit of the length of 1 cm for the real output size. The atomic ratio of O1s/Cu2p for Cu ultrasonically cleaned alone in the liquids tended to decrease in the order H\({}_{2}\)O \(\approx\) CH\({}_{3}\)OH > C\({}_{2}\)H\({}_{5}\)OH > (CH\({}_{3}\))\({}_{2}\)CHOH \(\approx\) C\({}_{3}\)H\({}_{7}\)OH. This may be related to the order of the amount of H\({}_{2}\)O being adsorbed on the surfaces after cleaning in each liquid because the adsorption of H\({}_{2}\)O most strongly decreases the \(N_{\rm T}\), as shown in Figure 5 (below). However, in the other cases, there was little relation between the \(N_{\rm T}\) and the order of O1s/Cu2p and C1s/Cu2p. The assignments of the XPS spectra before and after TPPE measurement in Figure 6 were conducted based on Refs. [30; 31; 32; 33] and our previous reports [27; 28]. The assignment of the XPS spectra on copper and oxygen is summarized as follows. The binding energy for the oxidation state of Cu is known as follows: 932.5 eV (Cu\({}^{0}\) and Cu\({}^{+}\)) and 933.5 eV(Cu\({}^{2+}\)) for Cu2p3/2; 335 eV (Cu\({}^{0}\)) and 337 eV (Cu\({}^{+}\) and Cu\({}^{2+}\)) for Cu\({}_{\rm LMM}\); a strong shake-up satellite structure 6-10 eV above the main Cu2p peak in Cu\({}^{2+}\) compounds. Concerning the Ols peak, [PERSON] [31] suggested that two components appearing at 529.9 eV and 532.5 eV for the oxygen chemisorbed copper can be assigned to oxygen bonded directly to copper and oxygen adsorbed onto the initial Cu-O structure, respectively. [PERSON] et al. [32] also suggested that the oxygen component of the higher binding energy component includes species such as OH, Cu(OH)\({}_{2}\), and H\({}_{2}\)O. Recently, the XPS spectra of starnished copper plates of phosphor bronze (C1220) (Cu purity: \(>\) 99.9%) were reported [33]. The binding energies of the Cu2p, the satellite, and O1s peaks were given as follows: Cu (932.6 eV), Cu\({}_{2}\)O (932.7 eV), and CuO (933.1 eV) for the Cu2p peak; 943-948 eV (Cu\({}_{2}\)O) and 940-945 eV (CuO) for the satellite peak; 531.7 eV (Cu(OH)\({}_{2}\)), 530.7 eV (Cu\({}_{2}\)O), and 529.8 eV (CuO) for the O1s peak [33]. In the Cu\({}_{\rm LMM}\), spectra for every sample abraded and ultrasonically cleaned before the TPPE measurement shown in Figure 6, metallic Cu clearly appeared at 335 eV, but after the TPPE measurement, the metallic Cu greatly diminished for almost all samples.