Neutral Ti for an atomic clock

Titanium is a candidate for laser cooling and has possible clock transitions in the telecom wavelength range. We carry out extensive calculations of energies, transition rates, lifetimes, branching ratios, and polarizabilities of neutral Ti to explore its potential for a development of an optical frequency standard. Titanium has four valence electrons and its electronic correlations are difficult to describe accurately. In this work, we use the CI+all-order method for that combines linearized coupled-cluster and configuration interaction (CI) approaches. We calculate transition rates and branching ratios for potential laser cooling and clock transitions. Ten forbidden transitions between the first 5 low lying even levels of neutral Ti are considered. Magnetic-dipole (M1) and electric-quadrupole (E2) reduced matrix elements were obtained in the random-phase approximation (RPA). For the potential clock transition from 3d³(⁴F)4s ⁵F₁ level to the ground state 3d²4s^{2 3}F₂ blackbody radiation (BBR) shift was also calculated. Good agreement between the experimental and computed energy levels and Lande g-factors confirms the fidelity of the obtained results and the accuracy of the CI+All-order method for Ti.