Neon emission lines

Table 10.1. Frequency Shifts (in Air) of Neon Emission Lines Relative to 514.532 nm...

When the current flows, metal atoms are sputtered from the cathode into the area within and in front of the cup. Collisions with the neon or argon ions cause a proportion of the metal atoms to become excited and emit their characteristic radiation. The choice of filler gas depends on the element lead, iron, and nickel perform far better with neon than with argon however, neon is not suitable with some elements, such as lithium and arsenic, because a strong neon emission line is close to the best resonance line. For many elements, there is little to choose between the two gases. 

If a neon lamp is available, the Ne emission lines may be used to obtain high-frequency calibration in a wide frequency range. Figure 2-14 shows the... 

We have developed a novel ultrasensitive detection method, thermal lens microscopy (TLM), for nonfluorescent species [13]. TLM is photothermal spectroscopy under an optical microscope. Our thermal lens microscope (TLM) has a dual-beam configuration excitation and probe beams [13]. The wavelength of the excitation beam is selected to coincide with an absorption band of the target molecule and that of the probe beam is chosen to be where the sample solution (both solvent and solute) has no absorption. For example, in determination of methyl red dye in water, cyclohexane, and n-octanol, a 514-nm emission line of an argon-ion laser and a 633-nm emission line of a helium-neon laser were used as excitation and probe beams, respectively [21], Figure 4 shows the configuration and principle of TLM [13]. The excitation beam was modulated at 1 kHz by an optical chopper. After the beam diameters were expanded, the excitation and probe beams were made coaxial by a dichroic mirror just before they were introduced into an objective lens whose magnification and numerical aper-... 

An electronic energy-level diagram determined from the laser-induced fluorescence spectrum of 9-hydroxyphenalenone [6] in a neon matrix is shown in Fig. 3. An emission line from the lowest vibrational level in the Si state is found to be split into a doublet. The energy difference between these two lines... 

A low-pressure atomic emission lamp such as neon or argon emits atomic lines of sufficiently narrow linewidth to be considered infinitely narrow for most Raman spectrometers (an example is shown in Fig. 10.1). The width of atomic emission lines depends on temperature and pressure, but is generally... 

The reference line may he from an impurity in the hollow cathode, a neon or argon line from Ihe gas contained in Ihe lamp, or a nonresonani emission line of Ihe element that is being determined. I mforlunaiely, a suitable reference line is often not available. 

The narrow emission lines which are to be absorbed by the sample are generally provided by a hollow cathode lamp—ue, a source filled with neon or argon at a low pressure, which has a cathode made of the element being sought. Such a lamp emits only the spectrum of the desired element, together with that of the filler gas. The considerations afiFecting the design and choice of lamps will be treated later in some detail. 

The choice of the inert gas depends upon two factors. Firstly, emission lines of the filler gas must not coincide with the resonance lines of the analyte element. The main emission regions from neon and argon are shown in Figure 19. The filler gas used in the hollow cathode lamp is easy to detect... 

Several examples of possible spectral line interferences include sodium at 2852.8 A with magnesium at 2852.1 A, iron at 3247.3 A with copper at 3247.3 A, and iron at 3524.3 A with nickel at 3524.5 A. Spectral interferences also are possible from hollow cathode lamps. The fill-gas of a hollow cathode lamp is commonly argon or neon and the lamps emit the line spectrum of the fill-gas as well as that of the hollow cathode material. The fill-gas therefore must be one that does not produce an emission line at the desired wavelength of the hollow cathode element. 

A-em 460 nm DAPI bound to DNA has a broad emission spectrnm >100 nm) and analyzed by confocal microscopy see Note 10, Fig. 24.2). Confocal microscopy is performed nsing a 63 X oil objective. The UV laser is used to excite DAPI at 405 nm with detection set between 419 and 456 nm. The 488 nm line of the argon ion laser is used to excite DiO with detection between 500 and 525 nm, and Dil is excited with the helium-neon laser line at 543 nm with detection of emission between 600 and 700 nm. Intensity and contrast of each acquisition channel are adjusted using the glow over under option of the Leica Confocal Software see Fig. 24.3a). 

Figure 12 Calibration spectrum used for the CCD echelle spectrograph. The lower curves represent the white-light response for the different echelle orders used. The lines represent atomic emission lines from a neon lamp used for wavelength calibration. (Adapted with permission from Ref. 133.)...

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