Knowledge Bank

For triangular triatomic molecules of the $XY2$-type, the choices of phase for the normal, coordinates of the totally symmetric modes $\nu 1$ and $\nu 2$ determine the signs of the Coriolis coupling constants $\zeta 13$ and $\zeta 23$ as well as those of other molecular constants. In particular, since the cubic potential constants are defined in terms of the normal coordinates, their signs must be consistent with the above choices of phase. Reexamination from this point of view of the calculation of the sextic centrifugal distortion constants of ozone by Chan and $Parker1$ revealed that some of the potential constants were used with the incorrect sign. We have now recalculated the sextic centrifugal distortion constants using the correct signs. The theoretical expressions presented by Aliev and $Watson2$ were used in the present work in addition to those of Sumberg and $Parker,3$ used in the original calculation. The results obtained with each of the two theoretical formulations, including error bounds, will be presented and compared to recent experimental results.