O2($b^1 \Sigma _g^ +$b1Σg+, υ = 0, 1) relative yields in O(1D) + O2 energy transfer

Abstract

Energy transfer from O((1)D) to O2 is the main source of O2(b(1)Σ(+)(g) in vibrational levels υ = 0 and 1 in the Earth's thermosphere. Knowledge of the relative yields for O2(b(1)Σ(+)(g) production in υ = 0 and 1 is essential for a reliable interpretation and modeling of the O2 atmospheric band emissions (b(1)Σ(+)(g) - X (3)Σ(-)(g) from these two vibrational levels. We report laboratory measurements of the relative yields at room temperature. In the experiments, O2(b(1)Σ(+)(g), υ = 0, 1) is generated by O((1)D) + O2 collisions following partial photodissociation of O2 at 157.6 nm. O2(b(1)Σ(+)(g), υ = 0, 1) emission detection is used to monitor the temporal evolution of the vibrational level populations. The measured fractional yield for υ = 1 is 0.8 ± 0.1, in contrast with the results of previous studies that indicated dominant O2(b(1)Σ(+)(g), υ = 0) production. A revision is warranted of the values used for these relative yields in atmospheric models.

Atmospheric dayglow diagnostics involving the O2(b‐X) Atmospheric band emission: Global Oxygen and Temperature (GOAT) mapping

“…Notably, this fact is only revealed when background interferences are subtracted and the large quenching correction is carried through. Laboratory studies of the production yields for the v = 0, 1 levels have shown that the nascent b ( v = 1) yield is 0.8 ± 0.1 [ Pejaković et al ., ]. Although an earlier study [ Lee and Slanger , ] reported that the nascent v = 1 yield was only ~0.4, a reanalysis of that data suggests that the actual number is significantly higher due to leakage through some of the detection filters used.…”

“…Laboratory studies of O( 1 D ) + O 2 were carried out at SRI International (SRI), where the emphasis was to determine the relative nascent yields of the v = 0, 1 vibrational levels, and their temperature dependence. An earlier study [ Lee and Slanger , ] concluded that ~40% of the O 2 ( b ) product was in the v = 1 level, but the most recent studies determined a value of (80 ± 10)% and little or no temperature dependence [ Pejaković et al ., ; Kostko et al ., ].…”

“…Subsequently, we learned that O( 3 P ) is at least as important a thermospheric quencher as O 2 [ Pejaković et al ., ]. Thus, it is worthwhile highlighting the fact that the conclusions reported here were enabled by a multiyear program of laboratory investigations performed at SRI International aiming to elucidate the essential components: (1) the relaxation of b (1) by ground‐state O 2 [ Bloemink et al ., ; Hwang et al ., ], (2) the relaxation of b (1) by O( 3 P ) [ Pejaković et al ., ], and (3) the relative yield of b (1) and b (0) following O( 1 D ) + O 2 energy transfer [ Pejaković et al ., ].…”

A new mechanism for OH vibrational relaxation leading to enhanced CO2 emissions in the nocturnal mesosphere

“…Lee and coworkers at SRI International [ Lee , ; Lee et al ., ] used laser radiation at 248 nm (5.00 eV) and 193 nm (6.42 eV) to photodissociate HO 2 formed by three‐body recombination of H + O 2 . They observed emission from the O 2 ( b → X ) Atmospheric band near 762 nm that was attributed to production of the O 2 ( b 1 Σ g + ) state following energy transfer from O( 1 D) to ground state O 2 [ Pejaković et al ., ; Lee and Slanger , ]. Lee [] concluded that excited O( 1 D) and ground state OH( 2 П) are the primary products from HO 2 photodissociation at these two wavelengths.…”

A previously unrecognized source of the O 2 Atmospheric band emission in Earth’s nightglow

“…The O( 1 D ) atoms generated by the OH(high v ) + O multiquantum vibrational relaxation process also provide a significant source of O 2 AB emission. O( 1 D ) atoms rapidly transfer energy to ground-state O 2 and generate electronically excited O 2 ( b ) molecules ( 28 , 29 )normalO(1italicDfalse)+O2→O2false(italicb,italicv=0,1false)+normalO(3italicPfalse)…”