Rotational Relaxation Studies of Hydrogen Fluoride

Rotational Relaxation Studies of Hydrogen Fluoride
Author: J. J. Hinchen
Publisher:
Total Pages: 33
Release: 1982
Genre:
ISBN:

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Laser double resonance experiments in HF were extended to probing levels as high as J=13 to define the processes of population transfer between rotational levels and transfer from vibration to rotation. In the first part of this report rotational transfer experiments are described and the results are compared with three different kinetic models. Using the criteria of transfer rates and signal shapes for evaluation, the Polyani-Woodall model was found to best describe the data. The second part of the report describes observations of direct transfer of vibrational (V=1) transfer to rotational levels J=10-13 of V=0. Very fast transfer by this route was measured but only a small fraction of the V=1 population was involved. Dilution of the HF sample by rare gases was found to enhance V-R transfer in accord with observations reported for rotational HF lasers.

Pulsed Hydrogen-fluoride Laser

Pulsed Hydrogen-fluoride Laser
Author: Ross McLeary
Publisher:
Total Pages: 4
Release: 1984
Genre: Gas lasers
ISBN: 9780642079510

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This report describes a pulsed hydrogen-fluoride laser which has been constructed at MRL. The laser delivers an energy of 7 J in a microsecond pulse from vibrational-rotational transitions in the wavelength region 2.6-3.1 micrometers. It simultaneously produces 1 mJ of energy in a 1 microsecond pulse from pure rotational transitions in the wavelength region 10-17 micrometers. Originator furnished keywords include: Chemical lasers, Hydrogen fluoride lasers, Electric discharge, Pulse discharge.

The Status of Rotational Nonequilibrium in HF Chemical Lasers

The Status of Rotational Nonequilibrium in HF Chemical Lasers
Author: N. Cohen
Publisher:
Total Pages: 75
Release: 1986
Genre:
ISBN:

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Because of the complexity of accounting simultaneously for gas dynamics, optics, and chemical kinetics in HF chemical lasers all computer modeling codes have simplified drastically at least one of these factors. One way to simplify the details of state to state chemistry is to ignore the possibility of rotational nonequilibrium. Rotational nonequilibrium can affect laser power and energy output, time to onset and duration of lasing, and power spectral distribution. This report will review, in turn, evidence for rotational nonequilibrium in HF chemical lasers; processes that can lead to rotational nonequilibrium in HF lasers; rotational relaxation of HF; and modeling studies of rotational nonequilibrium effects in HF chemical lasers. Keywords: Chemical lasers; Hydrogen fluoride; Energy transfer; Rotational relaxation; and Rotational energy transfer.

Rotational Relaxation Measurements and Resonant Phenomena in Laser-Excited Hydrogen Fluoride

Rotational Relaxation Measurements and Resonant Phenomena in Laser-Excited Hydrogen Fluoride
Author: G. H. Lindquist
Publisher:
Total Pages: 55
Release: 1974
Genre:
ISBN:

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Rates for the transfer of rotational energy (R-R) in vibrationally excited HF gas were measured using a single laser pump-probe technique. The relaxation time was found to be inversely proportional to HF pressure in the mTorr range and the self-relaxation rate constant was determined. Rotational relaxation of HF gas due to the presence of additive gases was observed. The relaxation rate for H2 was measured. The temporal evolution of HF laser pulses was examined and compared with the vibrational fluorescence of the laser discharge and the temporal gain of the discharge. The importance of hydrogen in the discharge is discussed. Reported observations of several resonant processes include bleaching, self-induced transparency, optical nutations, and an anomalous increase of 40 in the refractive index. (Modified author abstract).

Rotational Nonequilibrium Influences in CW HF/DF Chemical Lasers

Rotational Nonequilibrium Influences in CW HF/DF Chemical Lasers
Author: S. W. Zelazny
Publisher:
Total Pages: 9
Release: 1981
Genre:
ISBN:

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A theory is presented which considers either rotational equilibrium or nonequilibrium rate processes in continuous wave (CW) hydrogen fluoride (HF) or deuterium fluoride (DF) lasers. The theory is used to predict zero power gain and power spectral distributions and comparisons are made with experimental observations. The DF reaction kinetics model was found to give predictions of zero power gain which were closely correlated with experimental data. However, the HF reaction kinetics were found to produce radically different zero power gains than experimentally observed. Modifications to the reaction rages of certain vibrational-translational and vibrational-vibrational energy exchange processes were found to remove the discrepancy between the measured and predicted zero power gains. The rotational nonequilibrium theory was used to predict the power spectral distributions for HF and DF lasers and results were found to be consistent with experimental data.