Intensities of hot bands in the dimol emissions of singlet molecular oxygen, O2(1? g )

Abstract

The temperature dependence of the three dimol emissions of oxygen 02(lAg) at 579,634 and 703 nm has been studied between 295 and 1500 K with a discharge-flow-shock-tube apparatus. The intensity increases with temperature and concentration as expected for these bimolecular processes, but there is a further increase which is attributed to the appearance of overlapping hot-band emissions from vibrationally excited molecules of OZ('Ag). For the 703 nm emission there is an additional contribution from hot bands of O2(*Zi).

Mitochondrial respiratory complex I probed by delayed luminescence spectroscopy

“…In consequence, we propose that red DL is most likely produced via dimol photoemission generated by two colliding molecules of singlet oxygen ( 1 O 2 ). Dimol luminescence can be observed at the characteristic wavelengths of 579, 634, and 703 nm, 107,108 with main emission at 634 nm. Thus, increased levels of superoxide produced by the semiflavone at the FMN-b [Figs.…”

Singlet-Oxygen Chemiluminescence in Peroxide Reactions

“…To be noted is the finding that the radiative rate constant estimated 86 for ( 1 O 2 ) 2 is larger than that reported ,− for 1 O 2 ( 1 Δ g ). Furthermore, it has been shown that the dimol luminescence intensity at 580, 633, and 703 nm (gas phase) depends on temperature . Additionally, Chou et al noticed that the integrated intensity ratio of the dimol emission bands for the 0,0 (633 nm) versus 0,1 (703 nm) transitions in CCl 4 solution depends on the triplet-oxygen concentration.…”

“…Furthermore, it has been shown that the dimol luminescence intensity at 580, 633, and 703 nm (gas phase) depends on temperature. 92 Additionally, Chou et al 84 noticed that the integrated intensity ratio of the dimol emission bands for the 0,0 (633 nm) versus 0,1 (703 nm) transitions in CCl 4 solution depends on the triplet-oxygen concentration. It was suggested 84 that triplet oxygen may interact with the ( 1 O 2 ) 2 collisional pair.…”

Dimol Emission of Oxygen Made Possible by Repulsive Interaction

“…The red light emitted by singlet molecular oxygen is a standard textbook example of chemiluminescence, , and has a long history of experimental − and theoretical ,− investigations. The energy of the strongest band of the emitted light is approximately twice as large as that of the vertical O 2 ( a 1 Δ g ) → O 2 ( X 3 ∑ g – ) transition, which is spin-forbidden.…”

“…Since the emission starts from short-lived excited species and requires the intermolecular interaction of two systems in which the corresponding transitions are forbidden individually, the signal is very weak and relatively hard to study experimentally. , The spectral characteristics, the band position and shape, along with their temperature dependence, were recorded long time ago, ,, while the corresponding rate constantswhich also require the determination of the concentration of the transient O 2 ( a 1 Δ g )were reported recently by Zagidullin et al , The theoretical investigations performed so far mostly concerned the potential energy surfaces of the electronic states − that determine the geometry and binding energy of the dimer complex. These studies showed that the O 2 –O 2 intermolecular potential is predominantly repulsive, and shows only a shallow van der Waals minimum at large intermolecular separation with very small binding energy …”