HYDROGEN BALMER ALPHA LINE-SHAPES FOR HYDROGEN-ARGON MIXTURES IN A LOW-PRESSURE RF DISCHARGE

The spectral and spatial profiles of atomic hydrogen emission (the Bal mer lines H(alpha) and H(beta)) from a low-pressure rf (13.56 MHz) dis charge in H-2+Ar mixtures have been studied. The plasma emission was o bserved in a direction normal to the applied electric field. The H(alp ha) profiles exhibit central narrow components and wide components whi ch are due to Doppler broadening. Comparisons of the H(alpha) profiles in a pure hydrogen plasma with those in H-2+Ar mixtures show that col lisions of molecular hydrogen ions and hydrogen atoms with argon atoms play a significant role in the production of the H(alpha) profile sha pes.