Triplet4dstates ofH2: Experimental observation and comparison with anab initiomodel for Rydberg-state energies

Abstract

The triplet $4d$ states of ${\mathrm{H}}_2$ have been studied by using a tunable single-mode dye laser to excite metastable molecules in the $2p{}_{}{}^3{}_{}{}^{}\Pi _u^{}{}_{}{}^{}$ state to the $4s$ and $4d$ triplet states. Ninety-three transitions were detected and their line positions measured. Some of these states decay primarily by predissociation. A simple model for the energies of the Rydberg states was developed; the model depends upon the polarizability and quadrupole interactions of the Rydberg electron with the ${\mathrm{H}}_2^{+}$ core. It provides a remarkably good description of the measured energy intervals.