Resonance laser-induced processes and energy transformations in adsorbed layers

Ozone Activation on TiO2 Studied by IR Spectroscopy and Quantum Chemistry

“…The intensity distribution of the components in the spectra of isotopic mixtures with different enrichments enabled us to identify all the eight species on the assumption of a monodentate model. These new data confirmed by calculations, in addition to the existing basic knowledge, can be used in promising experiments on infrared laser-induced resonance photoozonolysis reactions [16].…”

“…If ozone is prepared from an isotopic oxygen mixture containing the excess of usual 16 O (about 57%), the intensities of the eight constituents are not equal, as can be seen from Figure 2, where the figures at each peak show the relative intensity with respect to the total intensity taken as 1. If the abundance of every isotopomer is purely statistical and the absorbance for ν 1+3 mode of all eight isotopic species is supposed to be the same (measurements for ozone isotopomers in liquid oxygen [14] show that for some vibrations it could be different for symmetrical molecules like 16 O 18 O 16 O and asymmetric molecules such as 16 O 16 O 18 O, but for the ν 1+3 mode the relative vibrational transition strengths are almost the same), then the relative intensities of molecules containing 0, 1, 2, or 3 18 O atoms for isotopically mixed ozone with 57% 16 O should be 0.185, 0.140, 0.105, and 0.08, respectively. A comparison of these figures with those in Figure 2 enables us to divide the three peaks of mixed isotopomers into two groups: those with intensities of 0.17-0.13 and those with intensities of 0.10-0.09.…”

“…The low-temperature stainless steel cell for studying the infrared spectra of adsorbed species was described elsewhere [11]. Ozone was prepared from gaseous 16 O 2 or its mixtures with 18 O 2 in the electric discharge and manipulated as previously reported. Before recording the spectra, about 0.5 Torr of helium was introduced into the cell to improve thermal contact of the sample with the cold environment.…”

“…If we adsorb the ozone prepared from a 50:50% isotopic mixture of 16 O and 18 O, then in the region of the ν 1+3 combination immediately after adsorption the structure of six bands arises, forming two triplets typical of symmetrical O 3 molecules, as in the spectrum of ozone adsorbed on aerosolized SiO 2 [1]. After about 1 h, these bands significantly lose their intensity and a group of more strongly held ozone molecules becomes visible, consisting of eight maxima of almost the same intensity, as shown in Figure 1 (solid line).…”