Applications of analytic continuation in the construction of potential energy curves

The representation of potential energy curves by continued fractions is investigated and shown to be a useful method in the extrapolation of data. A generalization of the method is presented that enables one to treat avoided crossing problems. Given data on one curve involved in the avoided crossing, it is possible to obtain a good approximation to the other. Results for various model calculations and for the H 2 (E. F 1 Σ + θ ) and CO ( 1 Σ + ) potential curves are presented.