The first direct radiative lifetime measurements in W I are described. Radiative lifetimes of 15 levels from the $5d^{4}6s\left(a{}_{}{}^6{}_{}{}^{}D\right)6p\left(z{}_{}{}^7{}_{}{}^{}D_{}^0{}_{}{}^{}\right)$, $5d^{4}6s\left(a{}_{}{}^6{}_{}{}^{}D\right)6p\left(z{}_{}{}^5{}_{}{}^{}F_{}^0{}_{}{}^{}\right)$, $5d^5\left(a{}_{}{}^6{}_{}{}^{}S\right)6p\left(z{}_{}{}^7{}_{}{}^{}P_{}^0{}_{}{}^{}\right)$,, and $5d^{4}6s\left(a{}_{}{}^6{}_{}{}^{}D\right)6p\left(z{}_{}{}^5{}_{}{}^{}P_{}^0{}_{}{}^{}\right)$ terms are reported with an accuracy of ±5%. The lifetimes are measured using time-resolved laser-induced fluorescence and a novel atomic-beam source. This novel hollow cathode effusive beam source produces an intense beam of ground-state W atoms and metastable W atoms.

• Received 30 April 1981

DOI:https://doi.org/10.1103/PhysRevA.24.2847