Shock Tube Measurement of Pb I Lines

Abstract

Oscillator strengths of lead atom spectral lines have been measured by observing the radiation emanating from gas samples heated to 10 000°K in a pressure‐driven shock tube. Shocks were produced by allowing hydrogen at high pressure to rapidly expand into dilute mixtures of tetraethyllead and neon. The thermodynamic state of the spectroscopically interesting gas behind the reflected shock was computed by using the measured shock velocity to estimate the state of an ideal gas, then using the state variables so derived to estimate the energy consumed in real gas effects, and completing the cycle by recalculating the state variables. Spectroscopic observations were made with a double prism spectrograph coupled with a revolving drum camera. The Stark broadening of Hβ was used to measure the electron density of the gas behind the first reflected shock. Quantitative spectroscopic analysis of lead atom emission lines led to the following absorption f‐values: λ = 3639, f = 0.04; λ = 3683, f = 0.07; λ = 4057, f = 0.15.