Two-step laser excitation of 4snd 3D1,2,3 and 4sns 3S1 states from the 4s4p 3P levels in zinc

Abstract

We present new experimental data on the term energies and quantum defects of the even-parity triplet states of zinc using a two-step laser excitation scheme in conjunction with a thermionic diode ion detector. The first laser was fixed at 32 501.399 cm−1 to populate the 4s4p 3P1 intermediate level. The 4s4p 3P0,2 fine structure components get populated through collisional energy transfer. The second laser was scanned covering the energy region 43 200 to 42 000 cm−1 revealing the highly excited states up to the first ionization limit. Our observations include 4snd 3D2 (14 ⩽ n ⩽ 55) and 4sns 3S1 (15 ⩽ n ⩽ 35) Rydberg series excited from the 4s4p 3P1 level. In addition, 4snd 3D3 (13 ⩽ n ⩽ 49) and 4snd 3D1 (10 ⩽ n ⩽ 20) series including few members of the 4sns 3S1 series have also been observed from the 4s4p 3P2 and 4s4p 3P0 levels, respectively. The binding energy of 4s4p 3P1 has been determined as 43 267.93 ± 0.02 cm−1, which consequently yields the first ionization potential of zinc as 75 769.35 ± 0.05 cm−1, which is in good agreement with that reported previously.