Validity of actinometry to measure N and H atom concentration in N-2-H-2 direct current glow discharges

The validity of actinometry to measure N and H atoms in nitrogen-hydrogen d irect current (dc) glow discharges was investigated. The experiments were c onducted in positive columns of de glow discharges, in mixtures of N-2-xH(2 ), where x varies from zero to one, pressures between 133.33 and 533.32 Pa and discharge currents from 1 to 50 mA. The electric fields were measured b y electric probes (17 V cm(-1) < E < 32 V cm(-1)), and the gas temperatures (490 K < T-g < 910 K) were deduced from the rotational transitions of mole cular-band systems. The actinometry was performed using argon as the actino meter gas and compared with laser induced fluorescence measurements of grou nd-state atoms, in order to establish the limits of the validity of actinom etry. A theoretical approach was used in order to interpret the behaviour o f the emission lines. In nitrogen-hydrogen positive columns, the actinometr y method indicated the correct behaviour of the N atoms density in the rang e of zero to one for x and for H atoms in the region from x = 0 to x = 0.2.