Calculated vibrational states of ozone up to dissociation

Abstract

A new accurate global potential energy surface for the ground electronic state of ozone [R. Dawes et al., J. Chem. Phys. 139, 201103 (2013)] was published fairly recently. The topography near dissociation differs significantly from previous surfaces, without spurious submerged reefs and corresponding van der Waals wells. This has enabled significantly improved descriptions of scattering processes, capturing the negative temperature dependence and large kinetic isotope effects in exchange reaction rates. The exchange reactivity was found to depend on the character of near-threshold resonances and their overlap with reactant and product wavefunctions, which in turn are sensitive to the potential. Here we present global "three-well" calculations of all bound vibrational states of three isotopic combinations of ozone ((48)O3, (16)O2 (18)O, (16)O2 (17)O) for J = 0 and J = 1 with a focus on the character and density of highly excited states and discuss their impact on the ozone isotopic anomaly. The calculations were done using a parallel symmetry-adapted Lanczos method with the RV3 code. Some comparisons were made with results obtained with the improved relaxation method implemented in the Heidelberg multi-configuration time-dependent Hartree code.

Efficient method for calculations of ro-vibrational states in triatomic molecules near dissociation threshold: Application to ozone

“…This agrees well with results of Ref. 56 where 160 symmetric and 125 antisymmetric states were reported. Figure 5 shows energy of vibrational states (both symmetries) as a function of state number in the window 600 cm −1 below dissociation threshold, which gives information about density of states in this important part of the spectrum.…”

“…Our assignments go much higher in energy, although, as it was discussed above, some of them are not entirely certain. But, for the lowest 120 states our assignment fully agrees with those of Ndengué et al 56 We want to mention that we also carried out calculations of vibrational states using the older PES for O 3 , developed by Schinke and co-workers, 57 and compared our results with their results. They reported 185 bound states and, for the most part, our energies and assignments agreed with their results, with mean deviation of only 0.6 cm −1 through the entire spectrum, except several upper states where the assignment of Schinke was uncertain, and some of the states were missing.…”

“…Examples are states (2,0,5), (1,1,6), (1,3,5), (2,1,5), (2,0,6), and (2,3,4). Importantly, we found much better agreement between our computed energies and the energies reported by Ndengué et al 56 Deviations are presented in Table S-I and we see that they increase from only −0.08 cm −1 for the ground state at −8618.25 cm −1 , to about −1 cm −1 for the states at energies near −1000 cm −1 , and stay at that level for the upper states in Table S-I, up to energies −600 cm −1 . The difference is always negative and changes smoothly, which indicates some kind of a systematic, rather than random difference, more likely due to methodologies used, rather than the issue of convergence.…”

“…As for state assignments, Ndengué et al 56 provided assignments for the lowest 120 states only. Our assignments go much higher in energy, although, as it was discussed above, some of them are not entirely certain.…”

Dynamics of the O-Atom Exchange Reaction 16O(3P) + 18O18O(3Σg–) → 16O18O(3Σg–) + 18O(3P) at Hyperthermal Energies

“…Even if the three-atom complex lived longer, it would not be expected to achieve complete randomization of energy because of the relatively shallow potential well and the highly harmonic nature of the PES immediately below the dissociation limit. 24,45 It is thus not surprising that the maximum probability of reaction in plots of the angular distribution at various impact parameters for inelastically and reactively scattered products, respectively. The vast majority of inelastic collisions (Fig.…”