Determination of Ionization Potential of Calcium by High-Resolution Resonance Ionization Spectroscopy

Abstract

High-resolution resonance ionization spectroscopy has been utilized to determine a precise ionization potential of Ca. Three-step resonance excitation with single-mode extended-cavity diode lasers populates long and unperturbed Rydberg series of 4snp (¹P₁) and 4snf (¹F₃) states in the range of n=20–150. Using an extended Ritz formula for quantum defects, the series convergence limit has been determined to be 49305.9240(20) cm⁻¹ with the accuracy improved one order of magnitude higher than previously reported ones.