Measurement of the 2S13–2P23transition wavelength in heliumlikeTi20+

Abstract
We have measured the wavelength of the 1s2s S13–1s2p P23 transition in heliumlike Ti x x i using fast-ion spectroscopy of 216-MeV titanium ions. Our wavelength value of 389.49±0.07 Å is in agreement with the most recent calculated value of 389.57±0.04 Å, which includes both relativistic and quantum electrodynamic corrections for the two-electron system. We compare our result with earlier calculations and with measurements for this transition in other heliumlike ions.