Radio frequency discharges at 13.56 MHz in CH4(100%), CH 4(10%)/H2, and H2(100%) are investigated by time- and space-resolved optical emission spectroscopy. The spatiotemporal net-excitation profile of H(n=3) is presented and discussed. The absolute value of the net-excitation rate, the emission intensity, and the density of the optically allowed electronic excited species are also measured. The self-quenching rate of H(n=3) and CH(A) by H2 and CH4 are estimated and compared with the previous works. The importance of the quenching of CH(A) by atomic hydrogen is also discussed. Excitation by very high-energy electrons is shown from the difference of the emission profile between H α and H2(d3Πu→a 3Σg+) in H2 at 100 kHz.
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