VUV fluorescence following photodissociation of N2O at 193 nm

Abstract

Photolytic studies performed at 193 nm demonstrate that NO in the highly excited D(v = 1,5) and E(v = 0) states is generated from N2O during irradiation in three sequential steps involving photodissociation, chemical reaction, and photoexcitation. The resulting NO fluorescence (160–230 nm) was analyzed with a system of rate equations, and the temporal behavior, intensity dependence, and pressure dependence were found to be consistent with a simple kinetic model. The quenching coefficient of NO by N2, Ar, and N2O were determined in this analysis to be qN2 = (2.7±0.8)×10−11 cm3 sec−1, qAr = (6.6±1.4)×10−11 cm3 sec−1, and qN2O = (1.5±0.4)×10−10 cm3 sec−1. Finally, dramatic changes in the spectral distribution of the ultraviolet NO fluorescence due to collisions with He were observed, which contrasts with the absence of spectral redistribution in collisions involving N2, Ar, and N2O.

N2O removal in N2 or air by ArF excimer laser photolysis at atmospheric pressure

“…Zavelovich et al [13] studied VUV fluorescence following photodissociation of N 2 O at 193 nm with an output energy of ∼80 mJ per pulse in the N 2 O pressure range of 133-26,600 Pa. They found that the dependence of the fluorescence intensity of NO emissions on laser intensity was linear even under unfocused conditions.…”

“…6(b). No significant enhancement of NO + On the basis of the above findings and known N 2 O photolysis under 193 nm [12][13][14], it was concluded that N 2 O decomposition diluted in N 2 initiates from selective one-photon-excitation of N 2 O followed by dissociation into O ( 1 D) and N 2 :…”

“…Since quantum yield of N 2 O at 193 nm is 1.0 [12][13][14], the following relation holds between mol numbers of n Pi (N 2 O) and those of O( 1 D) and N 2 produced through photodissociation process (2) in an ith laser pulse: …”

“…σ 2 = 8.95 × 10 −20 cm 2 molecule −1 [14] The quantum yield of O( 1 D) in photodissociation process (2) has been known to be 1.0 [12][13][14]. In the presence of O 2 , O 3 , and NO 2 , the following photodissociation processes occur simultaneously under 193 nm laser irradiation.…”

“…Since discharge processes are generally unselective for atoms and molecules, excitation, ionization, and dissociation occur simultaneously for N 2 O, N 2 , and O 2 by fast electron impact. Therefore, decomposition of N 2 [12][13][14]. Thus, an efficient and selective removal of N 2 O by 193 nm ArF excimer laser photolysis is expected in air.…”