Resonance ionisation spectrometry measurement of atomic calcium Rydberg isotope shifts

Rydberg levels in atomic calcium are of interest due to their use in highly isotope selective multiple-step resonance ionisation spectrometry, and also for nuclear physics investigations, but gaps remain in the data for higher lying levels in calcium isotopes other than ${}^{40}\text{Ca}$. We report novel isotope shift data on four isotopes of calcium (${}^{42}\text{Ca}$, ${}^{43}\text{Ca}$, ${}^{44}\text{Ca}$, ${}^{48}\text{Ca}$), relative to the majority abundance isotope ${}^{40}\text{Ca}$, in six Rydberg transitions for each P (n = 25–30) and F (n = 23–28) angular momentum quantum number designated series. (paper)