Quenching of by O(³P), O₂(a¹Δ_g), and other gases

Abstract

Spectroscopic and kinetic results for the quenching of [Formula: see text] are presented, including the first reported laboratory observation of gas phase emission from vibrational levels greater than zero for this state. In addition, the absolute rate constants for quenching of the lowest vibrational level by O(3P), O2(a1Δg), [Formula: see text], CO2, SF6, HE, and Ar are given. These results are compared with the results of atmospheric modeling studies. Qualitative evidence is presented for the formation of O2(a1Δg) and [Formula: see text] in the quenching of this state.

Collisional removal of O2(b 1Σg+,v=1,2) by O2, N2, and CO2

“…The second excited singlet state of O 2 , b 1 ⌺ g ϩ , is observed in various environments-in O 2 discharge flows, [1][2][3][4] in the terrestrial nightglow, [5][6][7][8][9] in the aurora, 10,11 and whenever the first excited state of atomic oxygen, O( 1 D), is generated in the presence of molecular oxygen. 12 However, almost all observations are made on the vϭ0 level, because the molecule has a long radiative lifetime 13 and collisional deactivation of vibrationally excited levels is rapid.…”

Collisional removal of O2 (c 1Σ−u, ν=9) by O2, N2, and He

“…The 1983 study of Kenner previous laboratory study to extract quantitative rate constants for the c 1 ⌺ u Ϫ state. 15 Using a nickel surface to enhance the production of excited electronic states of O 2 in a microwave discharge flow tube, they extracted removal rate constants for the lowest lying vibrational level with the colliders O͑ 3 P͒, O 2 (a 1 ⌬ g ), O 2 , CO 2 , SF 6 , N 2 O, He, and Ar. 15 These measurements are directly applicable to the atmosphere of Venus, where emission from ϭ0 dominates, but are less applicable to the terrestrial atmosphere, where emission from higher vibrational levels is important.…”

“…15 Using a nickel surface to enhance the production of excited electronic states of O 2 in a microwave discharge flow tube, they extracted removal rate constants for the lowest lying vibrational level with the colliders O͑ 3 P͒, O 2 (a 1 ⌬ g ), O 2 , CO 2 , SF 6 , N 2 O, He, and Ar. 15 These measurements are directly applicable to the atmosphere of Venus, where emission from ϭ0 dominates, but are less applicable to the terrestrial atmosphere, where emission from higher vibrational levels is important. In those experiments, many excited electronic states were produced at the Ni surface, and the accuracy of the measurements has been questioned due to the possibility of cascading and other complications.…”

“…16 Rate constants have also been extracted from nightglow observations, [16][17][18][19] and have been consistently much larger than those obtained from the laboratory work of Kenner and Ogryzlo. 15 Clearly, more laboratory work is needed to understand these discrepancies.…”

O2-triplet emissions in the nightglow

“…From [4] and [5], it would therefore seem that ao, > > a N 2 , the ratios of the efficiencies depending on k2 and k3. The latest values for k3 are from measurements by Kenner and Ogryzlo (32,33), who gave Until the same authors (34) published a value for k-, = (9.3 k 1.7) x 10-l5 cm3 .s-I, the rate constant in use had been k2 = 3 x 10-13 (17, 25, 37), which is comparable with k3.…”