LINE-SHAPE STUDY OF BA IONS IN LASER-PRODUCED PLASMAS

Detailed measurements of spatio-temporal variations in the line streng ths and line shapes for Ba ion absorption lines, observed in laser-abl ated YBCO plasma plumes, show that the presence of ambient oxygen lead s to enhanced local number densities and temperatures at the expanding front of the plasma plume. Enhanced local temperatures (and local exc itation rates) are attributed to the increased collisional redistribut ion of high initial z-directed plume velocities in the presence of amb ient oxygen.