Carbon monoxide lasers

Carbon Monoxide Laser Resonance Absorption Studies of 0(3P) + 1-Alkynes and Methylene Radical Reactions... 

The carbon monoxide laser normally operates at roughly twice the frequency of the CO2-laser. However, it can oscillate on several hundred lines between 4.8 and 8.4 jim [1,23]. This is due to the fact that many different vibrational levels in the deep, enharmonic potential curve of CO can be the starting point for laser emission. Under CW-condition, v=3= 2 up to v=37= 36-bands can be obtained and the frequency shift between adjacent bands is due to the anharmonicity of the CO-potential. The inversion mechanism is not as straightforward as in the CO2-laser. Usually no complete inversion for adjacent vibrational levels can be obtained and therefore only P-branch transitions do occur. Nevertheless, the wavelength region is completely covered with the rotational distribution of the vibrational bands (Fig.1.13). 

The dynamics of fast processes such as electron and energy transfers and vibrational and electronic deexcitations can be probed by using short-pulsed lasers. The experimental developments that have made possible the direct probing of molecular dissociation steps and other ultrafast processes in real time (in the femtosecond time range) have, in a few cases, been extended to the study of surface phenomena. For instance, two-photon photoemission has been used to study the dynamics of electrons at interfaces [ ]. Vibrational relaxation times have also been measured for a number of modes such as the 0-Fl stretching m silica and the C-0 stretching in carbon monoxide adsorbed on transition metals [ ]. Pump-probe laser experiments such as these are difficult, but the field is still in its infancy, and much is expected in this direction m the near fiitiire. 

Electronic excitation from atom-transfer reactions appears to be relatively uncommon, with most such reactions producing chemiluminescence from vibrationaHy excited ground states (188—191). Examples include reactions of oxygen atoms with carbon disulfide (190), acetylene (191), or methylene (190), all of which produce emission from vibrationaHy excited carbon monoxide. When such reactions are carried out at very low pressure (13 mPa (lO " torr)), energy transfer is diminished, as with molecular beam experiments, so that the distribution of vibrational and rotational energies in the products can be discerned (189). Laser emission at 5 p.m has been obtained from the reaction of methylene and oxygen initiated by flash photolysis of a mixture of SO2, 2 2 6 (1 )-... 

No information was found on the transformation of diisopropyl methylphosphonate in the atmosphere. Based on the results of environmental fate studies of diisopropyl methylphosphonate in distilled water and natural water, photolysis (either direct or indirect) is not important in the transformation of diisopropyl methylphosphonate in aquatic systems (Spanggord et al. 1979). The ultraviolet and infrared laser-induced photodegradation of diisopropyl methylphosphonate in both the vapor or liquid phase has been demonstrated (Radziemski 1981). Light hydrocarbon gases were the principal decomposition products. Hydrogen, carbon monoxide (CO), carbon dioxide (C02), and water were also detected. 

Sell, J. A. Herz, R. K. Monroe, D. R. "Dynamic Measurement of Carbon Monoxide Concentrations in Automotive Exhaust Using Infrared Diode Laser Spectroscopy" SAE Paper No. 800463, 1980. 

Lasers, 9 729 14 654-706. See also Lasing atomic systems in, 14 666-669 basic mechanism of, 14 656—661 buried heterostructure, 14 701 carbon dioxide, 14 693-696 carbon monoxide application, 5 24 cavity optics and, 14 669-672 classes of, 14 666-667 cutting applications of, 14 695-696 dye, 14 702-705 effect of loss in, 14 670 excimer, 14 691-693 fast pulse production in, 14 673-678 fiber optics and, 11 129 in fine art examination/conservation, 11 412, 413... 

Long-path infrared absorption, using a tunable diode laser, which is claimed to have a sensitivity of 5 ppb for carbon monoxide over a 610-m path length. ... 

Kreuzer, L. B., N. D. Kenyon, and C. K. N. Patel. Air pollution Sensitive detection of ten pollutant gases by carbon monoxide and carbon dioxide lasers. Science 177 347-349. 1972. 

Ku, R. T., E. D. Hinkley, and J. O. Sample. Long-path monitoring of atmospheric carbon monoxide with a tunable diode laser system. Appl. Optics 14 854-861, 1975. 

Sachse, G. W., G. F. Hill, L. O. Wade, and M. G. Perry, Fast-Response, High-Precision Carbon Monoxide Sensor Using a Tunable Diode Laser Absorption Technique, J. Geophys. Res., 92, 2071-2081 (1987). 

Since enthalpy changes can be obtained directly from measurement of heat absorption at constant pressure, even small values of AH for chemical and biochemical reactions can be measured using a micro-calorimeter.1112 Using the technique of pulsed acoustic calorimetry, changes during biochemical processes can be followed on a timescale of fractions of a millisecond. An example is the laser-induced dissociation of a carbon monoxide-myoglobin complex.13... 

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