Stark width measurements and Boltzmann plots of W I in nanosecond laser-induced plasmas

We report the first measurements of Stark broadening widths of W I lines (426.9 nm, 429.4 nm, and 430.2 nm) as a function of electron density, n e . The electron density is obtained from Stark broadening of a C II line at 426.7 nm in nanosecond laser-induced tungsten carbide plasmas. A linear relation between the W I Stark widths and n e is confirmed. The electron temperature, T e , is evaluated from Boltzmann plots of W I transitions with an oscillator strength f i k < 1.0 × 10 − 2 , since systematically lower population densities are observed for W I transitions with f i k ⩾ 1.0 × 10 − 2 , indicating that absorption occurs. This is consistent with an overestimated n e derived from Stark broadening of the 429.4 nm line ( f i k = 2.45 × 10 − 2 ) at a high ambient gas pressure.