Nuclear charge radii of neutron deficient titanium isotopes ⁴⁴Ti and ⁴⁵Ti

Optical isotope shifts of the unstable Ti-44.45 isotopes, as well as those of stable Ti16-50, have been investigated by collinear laser spectroscopy on fast ion beams using an ion guide isotope separator with a cooler-buncher. Changes in mean square charge radii across the neutron 1f(7/2) shell are deduced. The evolution of the even-N Ti nuclear radii shows a generally increasing tendency with decreasing neutron number. This behaviour is significantly different to that of the neighbouring Ca isotopes which exhibit a symmetric parabolic behaviour across the shell. The trend of the Ti nuclear radii is consistent with the predictions of the relativistic mean-field theory. The charge radius of Ti-44 is also compared to predictions of a Ca-40 + alpha cluster model.