Measurement of the Transition Probability of the O i Multiplet at 6157 A

A transition probability of 7.6×106 sec−1 for the 3p5P–4d5D° multiplet of O i at 6157 A was measured in a wall-stabilized high-current arc operating in an atmosphere of oxygen containing a trace of hydrogen. Electron densities were obtained from Hβ line-profile measurements, and upper-level populations were calculated as a function of electron density by assuming local thermodynamic equilibrium. The method minimizes the turbulence and “demixing” problems associated with earlier measurements. Special attention was given to the accurate determination of the background of the spectral lines.