Experimental derivation of Arrhenius equations for collisional quenching rate coefficients of Ar(³P₂) by Ar(¹S₀) and H₂O

Abstract

This paper presents the temperature dependence for the collisional quenching rate coefficient of the metastable excited atom Ar(3P2) by the water molecule H2O. A few papers reported on the collisional quenching rate coefficients of the metastable excited atom Ar(3P2) by the ground state atom Ar(1S0) and the water vapor molecule (H2O) have already been published; however, their temperature dependences have not been reported. We determined them experimentally by a nonspectroscopic method following our previous works on the metastables Ne(3P2) and . The effective lifetime of Ar(3P2) was measured in Ar and Ar/H2O mixtures in a Townsend discharge by a pulsed afterglow technique. The collisional quenching rate coefficients of the metastable excited atom Ar(3P2) by Ar(1S0) and H2O were determined as 1.22 × 10−15 and 2.31 × 10−10 cm3 s−1 at 300 K, respectively. The diffusion coefficient and reflection coefficient of Ar(3P2) at a cathode surface were also determined. Furthermore, the temperature dependences of both the collisional quenching rate coefficients were investigated and expressed as Arrhenius equations. The data are expected to enable the numerical simulation of the reaction between H2O and the metastable excited atoms produced by dielectric barrier discharges and atmospheric plasma jets in air plasma.

Atmospheric pressure argon plasma jets I – Measurements of spatial distribution for visible emission spectrum and vacuum ultraviolet

“…We reported 15 that N 2 (A 3 ∑ u + ) de‐excites in collision with H 2 O having the energy level diagram shown in Figure 3(C) (ionization above 15 eV is omitted) and measured rate coefficient of this reaction 16 ; eventually, this contributes to OH generation in Figure 3(D). On the other hand, we also measured rate coefficient of the collisional quenching of Ar( 3 P 2 ) by H 2 O 17 . Emission produced by excited state of OH due to H 2 O dissociation has a peak at 309 nm caused by the transition OH(A 2 ∑ + , v = 0) → OH(X 2 Π, v = 0); this is shown by brown and classified with Group VI.…”

“…We estimated the rate coefficient of this collisional quenching reaction as follows 17 $$$$\begin{equation}k = 2.75 \times 10^{ - 10}\ {\mathrm{cm}}^3/{\mathrm{s}}\end{equation}$$$$…”

“…On the other hand, we also measured rate coefficient of the collisional quenching of Ar( 3 P 2 ) by H 2 O. 17 Emission produced by excited state of OH due to H 2 O dissociation has a peak at 309 nm caused by the transition OH(A 2 ∑ + , v = 0) → OH(X 2 Π, v = 0); this is shown by brown and classified with Group VI. The spectrometric results presented so far can be interpreted as the process in which APJ is generated and maintained in Groups I-IV, while in Groups V-VI, argon active species formed through transitions of Groups 1-IV transmit energy to N 2 and H 2 O. and OH (VI) first increase at x from 0 to 7.5 -10 mm, as shown in diagrams (E) and (F), but then decrease together with argon peaks in diagrams (A)-(D).…”