Rydberg Terms of Acetylene

Abstract
It is assumed that two observed Rydberg series in acetylene correspond to (ns) and (nd) orbital excitation. Calculations in a one‐electron approximation support the assumption in both cases. The core is assumed to be frozen and linear and interatomic distances unchanged from normal state values in the Rydberg states and in the lowest state of the ion. The terms agree well with experimental values. The Rydberg functions are obtained as linear combinations of Slater functions and energies are stable to variation of both linear and nonlinear parameters.