Measurement of N2(A 3Σu+) metastable in N2 pulsed positive corona discharge with trace amounts of additives

The density of N(2)(A(3)Sigma(+)(u)) metastable is measured in various gases (N(2)/O(2), N(2)/NO, N(2)/NO(2), N(2)/H(2)O, N(2)/CO) after pulsed positive corona discharge using time-resolved laser-induced fluorescence (LIF) under atmospheric pressure. The N(2)(A(3)Sigma(+)(u)) density in N(2)/O(2)(0.25%) is uniformly distributed along the axis of the discharge gap (point-to-plane, 12 mm). This result indicates that N(2)(A(3)Sigma(+)(u)) is mostly generated in the primary streamer channels. The absolute N(2)(A(3) Sigma(+)(u)) density is measured by calibrating the LIF signal intensity. When the discharge voltage is 21.5 kV, the N(2)(A(3)Sigma(+)(u)) density immediately after the discharge pulse is estimated to be (2-3) x 10(13) cm(-3). The reaction rate constants of N(2)(A(3)Sigma(+)(u)) with O(2), NO, NO(2), H(2)O and CO are roughly estimated using the decay rate of N(2)(A(3)Sigma(+)(u)) density after the discharge pulse, and are compared with reference values. N(2)(A(3)Sigma(+)(u)) production is increased approximately twofold when hundreds of ppm of O(2), NO or NO(2) molecules are added to N(2).