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, ne. 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 ne is confirmed. The electron temperature, Te, is evaluated from Boltzmann plots of W I transitions with an oscillator strength f(ik) < 1.0 x 10(-2), since systematically lower population densities are observed for W I transitions with f(ik) >= 1.0 x 10(-2), indicating that absorption occurs. This is consistent with an overestimated ne derived from Stark broadening of the 429.4 nm line (f(ik) = 2.45x10(-2)) at a high ambient gas pressure.