Ion-number-density-dependent effects on hyperfine transition of trapped 199Hg+ ions in quadrupole linear ion traps

Abstract The ion-number-density-dependent frequency offsets and broadening of the ground state hyperfine transition spectra of trapped H 199 g + ions were measured as a function of the end-cap voltage of the quadrupole linear ion trap. The number density of trapped H 199 g + ions in the quadrupole linear trap was controlled by the end-cap voltage. The fractional frequency stability of H 199 g + hyperfine transition to the 1 mV end-cap voltage variation was preliminary estimated to be less than 1 × 10 − 16 . The causes of the ion-number-density-dependent frequency shift and spectrum broadening were analyzed theoretically and explained.