Rates and pathways of vibrational self-relaxation of HF(v=2) between 300 and 700 K

Abstract

The vibrational quantum number dependence of the collisional lifetime in nitric oxide selfrelaxation up to v'=25 A direct determination of the role of vibrationtovibration energy transfer in HF(v=3,4) selfrelaxation J. Chem. Phys. 84, 220 (1986); 10.1063/1.450174Vibrational relaxation of HF(v = 3, 4, 5) between 300 and 700 K The temperature dependencies of the total self-relaxation rate constants for the vibrational deactivation ofHF(v = 2) and HF(v = 1) and the state-to-state vibrationto-vibration (V-V) and vibration-to-translation-and-rotation (V-T,R) energy transfer components of the HF(v = 2) self-relaxation process are measured using the overtone vibration excitation-laser double resonance technique. The total self-relaxation rate constants vary inversely with temperature. The much weaker temperature dependence of HF(v = 2) self-relaxation compared to that of HF(v = I) arises from the significant role of the V-V energy transfer route. Competition between energetics and collision duration results in a weaker inverse variation with temperature for the slightly endothermic V-V route than for the exothermic V-T,R route for HF(v = 2).The branching ratio for V-V energy transfer increases slightly with temperature and the data suggest that two quantum relaxation processes constitute no more than 10% of the total self-relaxation of HF(v = 2). The available temperature dependence data on self-relaxation of HF(v = 1-5) form a consistent picture in which the energetics of the V-V and V-T,R relaxation pathways control their relative contributions to the total energy transfer.by direct overtone vibration excitation at -1.3 f.L. A fast ( -5 ns) InAs detector in conjunction with a transient 780

Vibrational Energy Transfer

“…The first experiments that had the chance to test the prediction of the linear quantum number dependence of V−RT energy transfer were performed with overtone pumping of HF. ,,− This resulted in a complex vibrational quantum number dependence that did not fit the predictions of theory. This work pointed out one of the characteristic self-relaxation mechanisms for molecules in v > 1: V−V energy transfer.…”

Dynamics Study of the O2(v) + HO2 Atmospheric Reaction

“…Examples of common and naturally occurring processes that lead to the formation of vibrationally excited molecules are exothermic chemical reactions, ultraviolet photodissociation, and electrical discharges. In fact, with the further development of stimulated emission pumping − and overtone pumping, − investigation of collisional properties of vibrationally hot molecules has blossomed. Moreover, for vibrationally excited diatomic species, fully quantum-state-resolved experiments are possible and quantum mechanical identification of all excited states is unambiguous.…”

“…These refer to the energetics of the O 2 (V ) 12-27) + HO 2 channels and relevant product ones. Note that for V ) 11 …”

“…11, the reactive channel leading to ozone formation is just barely open. However, for vibrational states V g 16, all reactive channels (O 3…”

Performances of a pulsed tunable infrared raman laser for spectroscopy

“…Another possibility to obtain conti-nuously tunable radiation in the IR is to produce a red-shift frequency conversion of the visible radiation emitted by a high power dye laser, owing to the stimulated Raman scattering in molecular gases [3][4][5][6]. Such Raman lasers have already been used for molecular physics measurements in the near IR [7,8]. We report here about the performances of a pulsed tunable Raman laser which can be wavelength-tuned continuously from the visible up to 6 itm.…”