## 3 Results and Discussion  
The absorption spectra of TiO\({}_{2}\) NP colloidal solution, were prepared by laser ablation at 1064 nm in deionized distilled water for 10 min at various laser pulse energies, are shown in Figure 2a. The recorded spectra showed an increase in the absorption intensity in the region from 200 nm to 300 nm with increasing laser energy, most likely resulting from increasing the concentration of TiO\({}_{2}\) NPs. Figure 2a showed an absorption peak in the UV region, at around 360 nm, resulting from band-to-band electrons transitions of TiO\({}_{2}\). It also depicted a smooth decay at longer wavelengths [5; 27]. Moreover, there are many parameters that affected the absorption behavior of TiO\({}_{2}\) NPs such as stoichiometry, morphologies, and size distribution [28]. Figure 2b shows the absorption spectra of TiO\({}_{2}\) NPs suspension solution synthesized with laser energy of 200 mJ at various irradiation times. The results show an increase in the absorption curves below 370 nm. This blue shift in the absorption values with irradiation times resulting from the quantum confinement effect [29]. Figure 3a illustrates the impact of irradiation energy on a concentration of prepared TiO\({}_{2}\) NPs. The results showed a gradual increase in the NP mass concentration with laser energy, most likely due to target evaporation at higher temperatures caused by high energy. Manufacturing the rate relies on several parameters concerning the optical and thermal properties of the metal target, such as the reflectivity, absorbance, heat capacity, enthalpy of vaporization, boiling point, and thermal conductivity. Figure 3b shows the variation of mass concentration with laser ablation times for the solution prepared at 200 mJ pulse\({}^{-1}\) laser irradiation energy. This figure showed a linear increase in mass concentration with increasing ablation time due to high particle concentration in the solution. Additionally, the ablation efficiency decreased with the ablation time due to two reasons: first, the presence of NP in liquid, which could interact with the laser beam and reduce the laser power on the surface; second, the metal surface modification by the irradiation of a pulsed laser, which could reduce the ablation efficiency. This is consistent with the results of [PERSON] et al. [30]. Figure 2: _Conts._  
Figure 4a shows the FTIR spectrum of the prepared TiO\({}_{2}\) NPs in the transmission mode. Results show that the peaks at 445.5 and 439.7 cm\({}^{-1}\) are attributed to the O-Ti-O vibration. The board peaks at 3425.3 and 3417.6 cm\({}^{-1}\) are assigned to O-H vibrations, while a peak -1641.3 cm\({}^{-1}\) is referred to as the Ti-O-H bending mode [31]. Figure 4: _Conts._  
Figure 3: Mass concentration of TiO\({}_{2}\) NPs at different (**a**) laser energies and (**b**) ablation time. Figure 2: UV–Vis absorption of TiO\({}_{2}\) NP solution synthesized at different (**A**) laser pulse energies and (**B**) ablation times. Figure 5 exhibits an XRD patterns of TiO\({}_{2}\) NPs synthesized in in deionized distilled water by laser irradiation (200 mJ pulse\({}^{-1}\): 10 min). A pattern shows intensity at 20 = 35.4\({}^{\circ}\) (101) and 38.8\({}^{\circ}\) (112) corresponding to the crystal formation of rutile and anatase TiO\({}_{2}\) (JCPDS: 21-1276 and JCPDS: 21-1272) phase, respectively [18]. Moreover, an additional peak centered at 20 = 45\({}^{\circ}\) corresponding to (\(-\)403) plane phase assigned to the \(\beta\)-TiO\({}_{2}\) phase (JCPDS No. 46-1238). A grain size value (D) was determined using [PERSON]'s formula (aforementioned in the characterization section) are summarized in Table 1.  
Figure 6 shows TEM images of TiO\({}_{2}\) NPs. From the images, it is seen that particle size estimation of 11 to 26 nm and spherical in shape. Also, the same figure shows particle agglomeration due to Ostwald ripening phenomena and the electrostatic attractive force between NPs owing to the electric double layer on NPs surfaces [14; 32].