Observations and theoretical analysis of highly excited singlet and triplet states of cadmium

Abstract

We have recorded the - 50) bound Rydberg spectrum of cadmium. We have fully resolved the multiplet up to n = 19 and partially up to n = 24. Furthermore, we have observed the odd singlet and triplet 5sn f Rydberg series for n = 10 - 22 and n = 4 - 21, respectively. We have applied two- and three-step laser schemes to excite Cd vapour in a heat pipe-like oven which was operated as a thermionic diode for detection. Theoretical calculations were performed for the energies of the 5sn p and 5sn f series using perturbation theory with a zero-order model approximation. There is a good agreement between theoretical and experimental results for the 5sn p series, the deviation decreasing with n and being 1 - 2 for n = 50. The agreement for the 5sn f is satisfactory. From the quantum defect of the 5sn f series we approximate a value of the effective dipole polarizability of the ion of in units of the Bohr radius.

Two-step laser spectroscopy of the highly excited even-parity levels of cadmium

“…The 5sns 3 S 1 series (23 n 29) have been observed with good intensity. The lower members of the 5sns 3 S 1 series (6 n 16) are listed in the NBS table (Moore 1971), while a few higher members (31 n 39) have been reported by Vidolova-Angelova et al (1996).…”

“…Mies (1979) discussed the perturbations between the 5snd 1 D 2 series and the 5p 2 1 D 2 autoionizing resonance within the framework of quantum defect theory. To our knowledge, the only laser-based work on the bound states of cadmium was reported by Vidolova-Angelova et al (1996) who applied various excitation schemes and observed the 5snp 1,3 P (7 n 50), 5snf 1 F 3 (10 n 22) and 5snf 3 F 3 (4 n 21) series. The radiative lifetimes of the ns 3 S 1 (n = 6-8), nd 3 D 3,2,1 (n = 6-8), triplet states approached through the 5s5p 3 P 0 and 5s5p 3 P 2 metastable states were studied by Kerkhoff et al (1980).…”