Temperature- and species-dependent quenching of NO AΣ+2(v′=) probed by two-photon laser-induced fluorescence using a picosecond laser

Abstract

We report improved measurements of the temperature-dependent cross sections for the quenching of fluorescence from the A 2Sigma+(v'=0) state of NO. Cross sections were measured for gas temperatures ranging from 294 to 1300 K for quenching by NO(X (2)Pi), H(2)O, CO(2), O(2), CO, N(2), and C(2)H(2). The A 2Sigma+(v'=0) state was populated via two-photon excitation with a picosecond laser at 454 nm, and the decay rate of the fluorescence originating from A 2Sigma+(v'=0) was measured directly. Thermally averaged quenching cross sections were determined from the dependence of the fluorescence decay rate on the quencher gas pressure. Our measurements are compared to previous measurements and models of the quenching cross sections, and new empirical fits to the data are presented. Our new cross-section data enable predictions in excellent agreement with prior measurements of the fluorescence lifetime in an atmospheric-pressure methane-air diffusion flame. The agreement resolves discrepancies between the lifetime measurements and predictions based on the previous quenching models, primarily through improved models for the quenching by H(2)O, CO(2), and O(2) at temperatures less than 1300 K.

Laser diagnostics and their interplay with computations to understand turbulent combustion

“…Ongoing work on energy transfer processes [11] and particularly on quenching cross sections for NO [106] and CO [107] will allow for greater accuracy in the measurement of these important regulated pollutants.…”

Transient Mixing Enhancement of a Transverse Jet in Supersonic Cross Flow Using Pulse Detonation

“…The total fluorescence decay r the fluorescence natural decay rate, A, and the electro s evaluated using the Settersten database. [29][30][31] Lastly, f he probed ro-vibronic state, which was calculated using s ions [32] for the specific spin-split J state of NO probed vel of X ed and computed NO PLIF as the PD plume evolved downstre agreeing reasonably well with the NO PLIF, the CFD so he relative differences between the NO jet plume with on. Figure 9 shows the comparison between the NO e PD interaction.…”

Effects of collisions on electronic-resonance-enhanced coherent anti-Stokes Raman scattering of nitric oxide

“…The values for q ␣b and q ␣c are 0.26 and 0.17, respectively, 21 and A =5ϫ 10 6 s −1 . [21][22][23] In Eq. ͑5͒, we further simplify the quenching model by assuming both vibrational manifolds in the ground electronic state are equally populated by quenching.…”

“…22 Here, we consider results for quenching rates of Q =10 2 A, 10 3 A, and 10 4 A, with the electronic dephasing rate and RET rate being fixed at the values ␥ 0 pd and R 0 , respectively. Figure 3 presents the time evolution of the amplitude of the Raman coherence ͉ bc ͉ and the square of the amplitude of the electronic coherence ͉ ac ͉ 2 that depicts the behavior of the signal intensity.…”