Ab initiocalculations of forbidden transition amplitudes and lifetimes of the low-lying states inV4+

Abstract

We report electric quadrupole $(E2)$ and magnetic dipole $(M1)$ transition amplitudes of the first few low-lying states of quadruply ionized vanadium $({\mathrm{V}}^{4+})$, which are important in various experimental applications and astrophysics. To our knowledge, most of these presented results are determined for the first time in the literature. A relativistic multireference Fock-space coupled-cluster theory with single $(S)$, double $(D)$, and partial triple $(T)$ excitations is employed to compute the forbidden transition probabilities and lifetimes of the low-lying states in ${\mathrm{V}}^{4+}$. Estimations of different correlation effects arising through the above formalism have been highlighted by investigating core and valence electron excitations. A long lifetime is found for the first excited $3d\phantom{\rule{0.2em}{0ex}}^{2}D_{5∕2}$ state, which suggests that ${\mathrm{V}}^{4+}$ may be one of the useful candidates for many important studies.