where g(R) is the continuous "guiding potential" derived from the low-level data. This reduces to eq. ( ) in the case g(R) = 0. As in eq. ( ), the parameters of fM(R) are fitted to the high-level data. However, now they are only required to reproduce the difference in energy between the high-level and low-level data, which usually displays weaker structure and smaller magnitude than the high-level data alone.