Multi-step laser excitation of the highly excited states of zinc

We report experimental data on the highly excited states of zinc in the energy range 74,625–75,740 cm−1 using two-step laser excitation scheme in conjunction with a thermionic diode ion detector. The 4s4p 3P1 inter-combination level at 32501.399 cm−1 was populated using a frequency doubled dye laser. The 4s5s 3S1 level at 53672.28 cm−1 gets populated from the ASE (amplified spontaneous emission) of the second step dye laser. The Rydberg series 4snp 3P2 (12 ⩽ n ⩽ 60), 4snp 1P1 (16 ⩽ n ⩽ 30) and parity forbidden transitions 4sns 3S1 (19 ⩽ n ⩽ 44) have been observed. A two parameter fit to excitation energies of the observed series yields the binding energy of the 4s5s 3S1 level as 22097.03 ± 0.03 cm−1 and consequently, the first ionization potential of zinc is determined as 75769.31 ± 0.05 cm−1, that is in excellent agreement with the earlier work.