Two-photon spectroscopy of np and nf Rydberg states of atomic iodine.

Abstract

The two-photon resonant, three-photon ionization spectrum of atomic iodine in the ${\mathrm{I}}^{\mathrm{*}}$ $^{2}\mathrm{P}_{1/2}$ state is presented. The ${\mathrm{I}}^{\mathrm{*}}$ $^{2}\mathrm{P}_{1/2}$ state is produced by photodissociation of methyl iodide, and its two-photon excitation spectrum exhibits ${(}^{3}$${\mathrm{P}}_{2}$)np and ${(}^{3}$${\mathrm{P}}_{2}$)nf Rydberg series converging to the ${\mathrm{I}}^{+}$ $^{3}\mathrm{P}_{2}$ ground state. With use of this technique, the single-photon forbidden np and nf series are readily observed to n>30.