Stroboscopic Effect between Electronic and Nuclear Motion in Highly Excited Molecular Rydberg States

The Na₂ Rydberg states have been observed for 15 ⩽ n ⩽ 90 and 4 ⩽ J ⩽ 45. The evolution of the spectra is studied as a function of the relative values of ω_el, the electronic rotational frequency, and ω _N , the nuclear rotational frequency. The molecular eigenfunction is found to be pure Hund’s case a when kω _el= 2ω _N (k being an integer). This may be explained in terms of stroboscopic effects arising from the movement of the Rydberg electron relative to the ionic core.

PACS numbers: 33.80.Eh, 33.10.-n