Knowledge Bank

The reaction $Li+FH\to LiF+H$ is a prototype of alkali plus hydrogen halide reactions. Despite this fact, only semi-empirical and a qualitatively accurate {ab initio} potential energy surfaces have been calculated. The previous {ab initio} surface was significantly modified for fitting because its stationary points were not in agreement with experiment. But now a new and accurate potential energy surface has been calculated. Because it is the calculated PES from which {ab initio} scattering calculation extract such values as state selected cross sections, angular distributions and time delays, errors in the calculated surfaces compound the problem of getting experimental verification of the scattering calculations. And since scattering calculations to based upon energy values extracted from an interpolating function fit to the calculated surface, it is desired that the error in the interpolating function be as small as possible when compared to the original calculated PES. Thus, from a scattering standpoint, the availability of both accurate PES’s and reliable fits to these PES’s are very important. A number of fits to the calculated points will be presented along with some discussion of how well the global living functions represent these points.