Low-excited f-, g- and h-states in Au, Ag and Cu observed by Fourier-transform infrared spectroscopy in the 1000–7500 cm−1 region

Abstract

The infrared emission spectra of Au, Ag and Cu resulting from the laser ablation of metal targets in a vacuum were recorded using time-resolved Fourier-transform spectroscopy in the 1200–1600, 1900–3600, 4100–5000 and 5200–7500 cm−1 ranges with a resolution of 0.017 cm−1. The majority of the observed lines correspond to transitions between low-excited Rydberg (Nd10)nlj states of Cu (N = 3), Ag (N = 4) and Au (N = 5) with a principal quantum number n = 4, …, 10; the most prominent lines being due to transitions between the states with high orbital momenta l = 3, …, 5. This study reports 32 new lines of Au, 12 of Ag and 20 of Cu (with uncertainties of 0.0003–0.03 cm−1). From the lines observed here and in our previous works, we extract revised energy values for 85 energy levels (uncertainty 0.01–0.03 cm−1) of which eight levels of Au, three of Ag and four of Cu are reported for the first time. These newly reported levels have high orbital momentum l = 3, 4, 5.