Time-resolved observations of vibrationally excited NO X 2Π (v′) formed from collisional quenching of NO A 2Σ+ (v = 0) by NO X 2Π: evidence for the participation of the NO a 4Π state

2021 ◽  
Vol 23 (36) ◽  
pp. 20478-20488
Author(s):  
James D. Fletcher ◽  
Lucia Lanfri ◽  
Grant A. D. Ritchie ◽  
Gus Hancock ◽  
Meez Islam ◽  
...  

Time resolved observations of the products of NO A 2Σ+ collisional quenching show fast and slow components, consistent with the involvement of a reservoir state (a 4Π) through which a portion of the quenching occurs.


1994 ◽  
Vol 48 (9) ◽  
pp. 1118-1124 ◽  
Author(s):  
Sara Agrup ◽  
Marcus Aldén

Time-resolved laser-induced fluorescence (LIF) from CO molecules in hydrocarbon flames was studied. Collisional quenching constants were evaluated on the basis of the exponential decays. Effective lifetime in a methane/oxygen flame was observed to vary between 250 and 400 ps depending on the position within the flame, and from 400 to 600 ps in the non-sooty parts of an ethylene/air flame. Fluorescence, constituting simultaneous spatially and temporally resolved decays, was also registered from various sections along a laser beam that probed different parts of the flame. Spectral recordings revealed not only the expected CO peaks but also, in the ethylene flame, laser-induced emission from C2 Swan bands and from polyaromatic hydrocarbon (PAH) emission that affected the fluorescence time decay in the sooty part of the flame.



1968 ◽  
Vol 46 (2) ◽  
pp. 341-343 ◽  
Author(s):  
D. C. Tardy ◽  
C. W. Larson ◽  
B. S. Rabinovitch

A technique is described for the study of collisional deexcitation of highly vibrationally excited polyatomic molecules by use of externally activated competitive unimolecular reaction systems. This method has some advantages and is illustrated by the decomposition of chemically activated hexyl-3 radicals in the presence of H2 and CF4 as heat bath molecules. The former removes ~1.2 kcal mole−1 per successful collision; while for the latter a value in excess of 4.6 kcal is found so that CF4 behaves operationally like a strong collider.



1999 ◽  
Vol 19 (1-4) ◽  
pp. 75-78 ◽  
Author(s):  
Takakazu Nakabayashi ◽  
Hiromi Okamoto ◽  
Mitsuo Tasumi

Vibrational relaxation dynamics of trans-stilbene in the S1 state immediately after photoexcitation is studied by picosecond time-resolved anti-Stokes Raman spectroscopy with several pump and probe wavelengths. Pump-wavelength dependence of the anti- Stokes spectrum indicates that, when pump photons with high excess energy (≈5200cm-1) are used, the anti-Stokes Raman bands at 0 ps delay time arise from vibrationally excited transients with excess vibrational energy not thermally distributed in the molecule. Probe-wavelength dependence suggests that the vibrationally excited transients at 0 ps are mostly on the lowest excited vibrational levels, as far as the olefinic C═C stretching and the C–Ph stretching modes are concerned. The vibrational relaxation process of S1trans-stilbene is discussed on the basis of the observed results.





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