Theoretical study of $\mathrm{Hf}{\mathrm{F}}^{+}$ in search of the electron electric dipole moment

We report ab initio relativistic correlation calculations of potential curves for ten low-lying electronic states, the effective electric field on the electron, and hyperfine constants for the ${}^3\Delta _1$ state of a cation of the heavy transition metal fluoride $\mathrm{Hf}{\mathrm{F}}^{+}$, which it is suggested can be used in experiments to search for the electric dipole moment of the electron. It is shown that $\mathrm{Hf}{\mathrm{F}}^{+}$ has a deeply bound ${}^1\Sigma ^{+}$ ground state; its dissociation energy is $D_e=6.4\mathrm{eV}$. The ${}^3\Delta _1$ state is obtained as the relatively long-lived first excited state lying about $0.2\mathrm{eV}$ higher. The calculated effective electric field $E_{\mathrm{eff}}=W_d\mid \Omega \mid$ acting on an electron in this state is $5.84\times {10}^{24}\mathrm{Hz}∕e\mathrm{cm}$.