Photoionization of atomic iodine and atomic tellurium

Abstract

Mass-analyzed photoionization spectra have been obtained from beams of atomic iodine and atomic tellurium from their respective ionization thresholds to ∼ 19 eV. In each instance the ionization thresholds are confirmed. For iodine, most of the features in the autoionization resonance spectrum have been identified and assigned to several $s$- and $d$-like Rydberg series converging to the higher-ionization limits ${}_{}{}^3{}_{}{}^{}P_0^{}{}_{}{}^{}$, ${}_{}{}^3{}_{}{}^{}P_1^{}{}_{}{}^{}$, ${}_{}{}^1{}_{}{}^{}D_2^{}{}_{}{}^{}$, and ${}_{}{}^1{}_{}{}^{}S_0^{}{}_{}{}^{}$ of the $5s^{2}5p^4$ configuration. For tellurium we also observe autoionization resonance features assigned to $s$- and $d$-like Rydberg series converging to the higher-ionization limits ${}_{}{}^2{}_{}{}^{}D_{\frac{3}{2}}^{}{}_{}{}^{}$, ${}_{}{}^2{}_{}{}^{}D_{\frac{5}{2}}^{}{}_{}{}^{}$, ${}_{}{}^2{}_{}{}^{}P_{\frac{1}{2}}^{}{}_{}{}^{}$, and ${}_{}{}^2{}_{}{}^{}P_{\frac{3}{2}}^{}{}_{}{}^{}$ of the $5s^{2}5p^3$ configuration. In addition, a window-resonance series and additional peaks have been assigned as converging to the $5s5p^4{}_{}{}^4{}_{}{}^{}P_{\frac{5}{2}}^{}{}_{}{}^{}$ state of ${\mathrm{Te}}^{+}$, with quantum defect of ∼0.5 (modulo 1). In both elements, the $d$-like series exhibits anomalous resonance profiles similar to those in the heavier noble gases, with quantum defects of ∼0.4 (modulo 1). The $s$-like series has quantum defects of ∼0.0 (modulo 1). Some comparisons are made with many-body calculations on the related chlorine atom.