Mercury light emission

The situation at wavelengths below 2000 A has improved recently. The upper electronic state of benzene excited by absorption of the 1849-A line of mercury would be the 1 lu state.47 No light emission from this state has been reported and no evidence exists relative to crossover from this state to any of the various triplet states of lower energy. 

Many pesticides fluoresce sufficiently when excited at 254 nm to permit the advantageous use of the intense 253.7 nm emission from a mercury light source for excitation in a HPLC fluorescence monitor. 

The photonitrozation reaction has a very low quantum yield ( 0.7). However, if 60 kW lamps doped with thallium iodide are used to produce an intense light emission at 535 nm (nanometers), while reducing the intensity of the other mercury bands, 24 kg/h of oxime can be produced per lamp, or about 180 t/year. The only industrial development of this process is that of Toray in Nagoya. The high consumption of electridty restricts it to areas where this type of energy is available cheaply.. 

An early experiment was carried out by Cario and Franck in 1922, where they used a mixture of mercury and thallium vapor. When irradiated with the light of a special frequency belonging to mercury, the emission spectrum shows the spectra of... 

FIGURE 9.7 Light emission by different elements Light emitted from a mercury lamp (left) appears blue, and light emitted from a hydrogen lamp (right) appears pink. 

The broad continua and the line inversion shown in figures 12, 13 and 14 disappear when the light emission is recorded about 350 nsec after the start of the laser pulse. Then the laser pulse will have passed and the light emission is solely due to the decomposition process of the explosive. Particularly interesting are the initial and delayed emission spectra of mercury fulminate, shown in figure 15, which were recorded at z = 0 mm. 

In figure 16 a portion of the initial (a) and delayed (b) emission spectra of HMX is shown after irradiation with 248 nm laser light. Emission spectra of RDX are similar [39]. In these initial spectra, CN could be identified superposed onto a continuum. This is in contrast with the emission characteristics of mercury fulminate, which showed CN only after a time delay. No line inversion was observed. 

Figure 7.7 The line spectra of several elements. A, The line spectrum of atomic hydrogen. B, Unlike the continuous spectrum of white light, emission spectra of elements, such as mercury and strontium, appear as characteristic series of colored lines.

Mercury lamp UV light sources give distinct linear light emission output at three UV wavelengths 365.4 nm (1-line), 404.7 nm (H-line), 435.8 nm (G-line) [2]. (Emission spectra for mercury lamps are given in Chap. 14). 

Quochi, F., Orru, R., Cordelia, F., Mura, A., Bongiovanni, G., Artizzu, F., Deplano, P., Mercuri, L., Pilla, L., and Serpe, A. (2006) Near infrared light emission quenching in organolanthanide complexes. /. Appl. Phys., 99 (5), 053520-1-4. 

A 100 mL laboratory photoreactor with a mercury light lamp or a similar light source emitting at A < 400 nm (in case of a low-pressure Hg lamp with its main emission line at 254 nm or other sources emitting below 300 nm, it should be taken into account that a quartz glass setup is required), microdistillation setup, safety glasses, laboratory coat, and protective gloves. 

Ultraviolet light sources are based on the mercury vapor arc. The mercury is enclosed ia a quart2 tube and a potential is appHed to electrodes at either end of the tube. The electrodes can be of iron, tungsten, or other metals and the pressure ia a mercury vapor lamp may range from less than 0.1 to >1 MPa (<1 to >10 atm). As the mercury pressure and lamp operating temperatures are iacreased, the radiation becomes more iatense and the width of the emission lines iacreases (17). 

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