OBSERVATION OF HIGH ORDER SIDE BANDS IN THE SPECTRUM OF STORED **3He** plus IONS.

The absorption and emission of radiation from a moving atom is shifted by the Doppler effect. In the special case of a bound atomic system moving periodically about a guiding center, the Doppler effect generates side bands in the spectrum of the radiating atom. The first study of these side bands was made for the spectrum of ions stored in a radio-frequency (rf) quadrupole ion trap, where an ensemble of ions is bound practically harmonically in three dimensions. It was shown that low order side bands occur in the hyperfine structure (hfs) spectrum of the **3He** plus ion at separations determined by the various characteristic ion oscillation frequencies and that the spacings are determined by the ion trap operation voltages. This paper reports on the observation of high order side bands in the same system and present a theoretical interpretation valid within the limits of first order perturbation theory.

OBSERVATION OF HIGH ORDER SIDE BANDS IN THE SPECTRUM OF STORED 3He plus IONS. Conference Paper